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New WCR Research Outlines ‘Innovation Crisis’ in Green Coffee

Nick Brown | June 29, 2023

A new white paper published by the nonprofit World Coffee Research (WCR) suggests research and development (R&D) funding in the coffee sector continues to be woefully short if roasters and consumers want to continue to enjoy coffee as they know it today.

The study estimates that the world would need to invest approximately $452 million new dollars per year in agricultural research and development (R&D) over the next decade in order to maintain green coffee diversity and quality.

With lesser investments or the status quo, the coffee industry is likely to experience mass consolidation in coffee production, as well as a dramatic reduction in diversity in terms of quality arabica coffee varieties and their origins, the authors suggest. These phenomena will be precipitated primarily by climate change and stress on producers amidst increasing global demand.

The paper characterizes the $452 million financial benchmark as an “investment gap” and says that the global green coffee sector is facing an “innovation crisis.”

“ coffee plant ” by functoruser is licensed under CC BY 2.0 .

The research behind the paper was led by Dr. Mywish Maredia, a professor of development economics in the Department of Agricultural, Food, and Resource Economics at Michigan State University, and MSU Ph.D. student Jose María Martínez.

“This scale of underinvestment cannot continue if the world wants to continue drinking its favorite beverage,” Maredia said in an announcement shared by WCR. “Increasing global investments in coffee R&D to accelerate innovations across multiple countries can help reverse this trend and support the coffee sector to keep up with growing consumer demand and respond to the challenges of climate change and poverty, while avoiding further consolidation of production.”

WCR is a globally focused nonprofit based in Portland, Oregon, that relies on numerous funding sources for programming and operations, including contributions from the private sector. The organization is hosting a webinar with CEO Jennifer “Vern” Long and lead author Maredia on the research on Wednesday, June 12.

The new paper encourages investment throughout the coffee world, which the authors say has been woefully underfunded compared to other agricultural sectors and industries of comparable consumer value. The authors specifically identified the coffee sectors in parts of Latin America and Africa as most in need of R&D funding due to historic deficiencies.

The paper is rife with heretofore unpublished financial statistics regarding R&D investments in the sector.

It says the current global investment in coffee R&D is estimated to be $115 million per year, with 90% coming from the public sector and 10% coming from the private sector. That equates to just under half a cent per every dollar of green coffee produced globally, according to the researchers.

The authors also say that the total value of green coffee makes up about 4.8% of the total value of agricultural output in the 45 coffee-producing countries included in the analysis.

“Coffee should therefore make up a similar percentage of agriculture sector investments in these countries — yet today, the investment amount is a mere 1.8%,” the paper states.

The paper concludes that a nearly four-fold increase in R&D investments is needed in the coffee sector to further prevent consolidation and loss of commercial green coffee diversity.

Wrote the authors, “For an industry with a retail value of more than US$200 billion, this would mean setting aside less than 0.3 cents for every $1 of coffee retailed to consumers.”

Does your coffee business have news to share? Let DCN’s editors know here .

Nick Brown Nick Brown is the editor of Daily Coffee News by Roast Magazine.

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Tags: fundraising , Jose María Martínez , Michigan State University , MSU AFRE , Mywish Maredia , nonprofits , research , science , Vern Long , white papers , World Coffee Research

Demasiado pueril y estéril el articulo; respecto a la problemática que enfrentamos los productores. Lo importante es solucionar el tema de los precios de compra al productor y luego si , los recursos destinados a investigación y desarrollo. Como creer que un productor perdiendo su dinero en la realización de su actividad , le va a interesar lo que otros entes hagan en cuanto a investigación y desarrollo??? . Seguimos perdidos.

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Open access
Published: 14 July 2020

The effects of green coffee extract supplementation on glycemic indices and lipid profile in adults: a systematic review and dose-response meta-analysis of clinical trials

Omid Asbaghi 1 ,
Mehdi Sadeghian 2 ,
Morteza Nasiri 3 , 4 ,
Mahmoud Khodadost 5 , 6 ,
Azad Shokri 7 ,
Bahman Panahande 8 ,
Aliyar Pirouzi 9 &
Omid Sadeghi 10 , 11

Nutrition Journal volume 19 , Article number: 71 ( 2020 ) Cite this article

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The role of coffee consumption in the risk of cardiovascular diseases has been debated for many years. The current study aimed to summarize earlier evidence on the effects of green coffee extract (GCE) supplementation on glycemic indices and lipid profile.

We searched available online databases for relevant clinical trials published up to October 2019. All clinical trials investigating the effect of GCE supplementation, compared with a control group, on fasting blood glucose (FBG), serum insulin, total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were included. Overall, 14 clinical trials with a total sample size of 766 participants were included in the current meta-analysis.

We found a significant reducing effect of GCE supplementation on FBG (weighted mean difference (WMD): -2.35, 95% CI: − 3.78, − 0.92 mg/dL, P = 0.001) and serum insulin (WMD: -0.63, 95% CI: − 1.11, − 0.15 μU/L, P = 0.01). With regard to lipid profile, we observed a significant reduction only in serum levels of TC following GCE supplementation in the overall meta-analysis (WMD: -4.51, 95% CI: − 8.39, − 0.64, P = 0.02). However, subgroup analysis showed a significant reduction in serum TG in studies enrolled both genders. Also, such a significant reduction was seen in serum levels of LDL and HDL when the analyses confined to studies with intervention duration of ≥8 weeks and those included female subjects. In the non-linear dose-response analyses, we found that the effects of chlorogenic acid (CGA) dosage, the main polyphenol in GCE, on FBG, TG and HDL were in the non-linear fashions.

In conclusion, we found that GCE supplementation improved FBG and serum levels of insulin and TC. Also, there was a significant improvement in other markers of lipid profile in some subgroups of clinical trials.

Peer Review reports

Cardiovascular diseases (CVDs) are the number one cause of death worldwide [ 1 ]. Dyslipidemia and impaired glucose tolerance (IGT) are among the primary risk factors for the development and progression of CVDs and type 2 diabetes [ 2 , 3 ]. Reversal of these risk factors leads to a considerable reduction in the risk of these chronic diseases [ 4 , 5 , 6 , 7 ]. Although current guideline recommends dietary regulations as the first-line therapy for dyslipidemia and glucose disturbance, only a modest amelioration has been achieved using these methods [ 8 ].

Coffee is widely consumed in the world containing a range of phytochemicals. Previous studies have shown beneficial effects of coffee consumption on several health conditions including metabolic syndrome, type 2 diabetes, and vascular function [ 9 , 10 ]. The most commonly found phytochemicals in the coffee are phenolic compounds, primarily chlorogenic acid (CGA) [ 11 ]. CGA is the ester of caffeic acid with quinic acid that belongs to the family of hydroxycinnamic acid [ 12 ]. Anti-lipidemic and anti-diabetic properties of CGA have been demonstrated in animal studies [ 13 , 14 , 15 ]. However, findings from human clinical trials are not consistent [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. Green coffee extract (GCE) and its CGA showed hypolipidemic effects on serum levels of triglyceride (TG) and total cholesterol (TC) in patients with IGT [ 29 ] and those with non-alcoholic fatty liver disease [ 26 ]; however, the effects on circulating levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were inconsistent. Some studies showed a significant increase in serum HDL following GCE intake [ 17 , 19 ], while others could not find any significant results [ 20 , 21 , 24 ]. Considering insulin resistance, fasting blood glucose (FBG) or serum insulin significantly reduced following GCE administration in some studies [ 18 , 24 , 29 ], but no significant changes were observed in some others [ 23 , 27 ].

A previous meta-analysis of randomized controlled trials (RCTs) found increased levels of serum TC, LDL, and TG following coffee intake [ 30 ]; however, to our knowledge, there is no study summarizing available findings on the effects of green coffee consumption on glycemic indices and lipid profile. Therefore, we aimed to conduct a systematic review and meta-analysis to summarize current evidence on the effects of GCE supplementation on glycemic and lipid profiles in adults.

This study was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol for reporting systematic reviews and meta-analyses [ 31 ].

Search strategy

A comprehensive literature search was performed using online databases of PubMed, Scopus, Web of Science and Google Scholar up to October 2019. The aim of the search was to identify clinical trials that investigated the effects of GCE supplementation on glycemic indices and lipid profile in adults. The following keywords were used in the search strategy: (“Green coffee” OR “Green coffee extract” OR “Green coffee bean extract” OR “Chlorogenic acid” OR “Chlorogenic” OR “GCR” OR “CGA”) AND (Triglyceride OR Triacylglycerol OR TG OR cholesterol OR lipoprotein OR “very low density lipoprotein” OR VLDL OR “low density lipoprotein” OR LDL OR “high density lipoprotein” OR HDL OR “lipid profile” OR “fasting blood sugar” OR glucose OR insulin OR “ glycosylated hemoglobin” OR HbA1c OR FBS OR FBG). No restriction was considered for the time and language of publications. We conducted a manual search in the reference lists of the relevant studies to avoid missing any eligible publication. Unpublished studies were not considered.

Inclusion criteria

We included eligible studies that met the following criteria: 1) placebo-controlled clinical trials 2) those that performed on adult subjects (≥18 years old), 3) studies that administered green coffee extract in the forms of supplement or powder added to foods or beverages, 4) those that did intervention for at least 2 weeks, and 5) controlled trials that reported mean changes and SDs of glycemic indices or lipid profile throughout the trial for both the intervention and control groups or presented required information for calculation of those effect sizes. If more than one article was found for one dataset, the more complete one was selected. Clinical trials with an additional arm were considered as 2 separate studies.

Exclusion criteria

In the current meta-analysis, we excluded:1) in vitro and animal studies, 2) studies with a cohort, cross-sectional, and case-control design, 3) review articles, 3) trials without a placebo or control group.

Data extraction

The following information was extracted from each eligible clinical trial by two independent investigators: name of the first author, publication year, individuals’ characteristics (mean age and sex), design, sample size (control and intervention groups), type of intervention, dosage of GCE and CGA, duration of intervention, and mean changes and SDs of outcome variables throughout the trial for the intervention and control groups. When data for glycemic or lipid measures were reported in different units, we converted them to the most frequently used unit.

Risk of bias assessment

We used the Cochrane quality assessment tool to assess the risk of bias for each study included in the current meta-analysis [ 32 ]. This tool contained seven domains including random sequence generation, allocation concealment, reporting bias, performance bias, detection bias, attrition bias, and other sources of bias. Each domain was given a “high risk” score if RCT comprised methodological defects that may have distorted the results, a “low risk” score if the defect was considered ineffectual and an “unclear risk” score if the information was not sufficient to determine the impact. If the trial had “low risk” for all domains, it was labeled as a high-quality study with a totally low risk of bias. The risk of bias assessment was done independently by two reviewers.

Statistical analysis

Mean differences in changes of the outcome variables (FBG, insulin, TG, TC, LDL, and HDL), comparing GCE and control groups, were used to obtain the overall effect sizes. When mean changes were not reported, we computed them by considering changes in each outcome variable during the intervention. If outcome variables (FBG, TG, TC, LDL, and HDL) were reported in mmol/L, we converted them to mg/dl through available suitable formulas. We also converted standard errors (SEs), 95% confidence intervals (CIs), and interquartile ranges (IQRs) to SDs using relevant formulas [ 33 , 34 , 35 ] . To obtain the overall effect sizes, we applied a random-effects model taking between-study variations into account. Heterogeneity was determined by the I 2 statistic and Cochrane’s Q test. I 2 value > 50% or P < 0.05 for the Q-test was considered as significant between-study heterogeneity [ 36 , 37 ]. To find probable sources of heterogeneity, subgroup analyses were performed according to the predefined criteria including gender (both/male/female), length of intervention (≥8/< 8 weeks), baseline levels of glycemic and lipid measures (abnormal/normal levels) and participants’ compliance (acceptable/non-acceptable or unclear). To determine the non-linear potential effects of CGA dosage (mg/d) on glycemic and lipid indices, fractional polynomial modeling was executed. Due to the lack of information on the dosage of GCE in some included studies, we decided to perform non-linear dose-response analysis for CGA dosage. Sensitivity analysis was used to explore the extent to which inferences might depend on a particular study. The possibility of publication bias was evaluated by the formal test of Begg. The meta-analysis was carried out by the use of the Stata, version 11.2 (StataCorp). P value < 0.05 was considered as significant level.

After the initial search, a total of 1571 studies were identified. After removing duplicate publications, 976 articles remained, out of which 958 studies were identified as unrelated when screening for title and abstract. After assessing the full text of remained articles, we excluded one study in which the effects of GCE in combination with olive leaf and beetroot were assessed [ 38 ]. We also excluded a study by Salamat et al. [ 39 ] that reported data only for oxidized LDL, not the natural type. Two studies that were quasi-experimental with no control group were excluded as well [ 40 , 41 ]. Two RCTs were conducted on a similar dataset; however, due to assessing different outcome variables, both of them were included [ 21 , 25 ]. Finally, 14 studies remained for the current systematic review and meta-analysis [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], out of which 11 studies presented data for FBG [ 16 , 18 , 19 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ], 7 studies for serum concentrations of insulin [ 18 , 19 , 24 , 25 , 26 , 29 ], 13 trials for serum concentrations of TC [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ], and 12 trials for serum concentrations of TG, LDL, and HDL [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ]. Data on other glycemic indices including glycosylated hemoglobin A1c (HbA1c) ( n = 3) and homeostatic model assessment for insulin resistance (HOMA-IR) ( n = 2) were not sufficient for the meta-analysis. Flow diagram of study selection is presented in Supplemental Figure 1 .

Findings from the systematic review

Characteristics of the 14 clinical trials included in the current systematic review are illustrated in Table 1 . The total sample size of the selected studies was 766 adult participants including 380 subjects in the GCE group and 386 subjects in the control group. Studies were published from 2004 to 2019. Out of 14 included studies, 3 were performed in western countries [ 21 , 25 , 29 ] and others were conducted in Asia [ 16 , 17 , 18 , 19 , 20 , 22 , 23 , 24 , 26 , 27 , 28 ]. The dosage of GCE among the included studies was between 90 and 6000 mg/day. Also, the dosage of CGA, as the main polyphenol in GCE, was between 13.5 and 1200 mg/day. The duration of intervention varied from 2 to 16 weeks.

Of fourteen studies, six trials administered GCE in the form of supplement [ 16 , 19 , 23 , 24 , 26 , 29 ], while eight studies administered in the form of powder added to boiled water or other beverages [ 17 , 18 , 20 , 21 , 22 , 25 , 27 , 28 ]. Out of fourteen studies, two were performed on healthy individuals [ 22 , 27 ] and others were conducted on subjects with overweight or obesity, dyslipidemia, hypertension, metabolic syndrome, non-alcoholic fatty liver disease, impaired glucose tolerance and mildly xerotic skin. According to the Cochrane Risk of Bias Assessment tool, none of the clinical trials had a low risk of bias in all domains of this tool (Supplemental Table 1 ).

Among eleven studies on FBG, four trials reported a lowering effect of GCE supplementation on FBG levels [ 16 , 24 , 25 , 26 , 29 ] and the other trials revealed no significant effect. Only in two studies, GCE supplementation could reduce serum levels of insulin [ 19 , 25 ] while the other trials could not find any significant change. There were 12 clinical trials on serum concentrations of TG, from which two studies revealed a lowering effect [ 26 , 29 ], one study showed an increasing effect [ 17 ], and the others indicated no significant effect on serum TG concentrations following GCE supplementation. Out of thirteen studies on TC, 3 studies found a significant reduction in serum TC concentrations after supplementation with GCE [ 19 , 26 , 29 ]. Only one study revealed a reducing effect of GCE supplementation on serum concentrations of LDL [ 19 ] while others did not reach statistical significance. Among twelve studies on serum HDL levels, only two studies showed an increasing effect of GCE supplementation on serum concentrations of HDL [ 17 , 19 ] whereas others failed to find any significant effect.

Findings from the meta-analysis

All fourteen clinical trials were included in the meta-analysis. These studies included 766 participants aged 18 years and over. There was a trial with three intervention arms with different dosages of GCE compared with one control group [ 20 ]. This study was considered as three separate studies. In two studies, findings were reported separately for normocholesterolemic and hypercholesterolemic participants [ 21 , 25 ]. Therefore, we considered each study as two separate studies.

The effect of GCE on FBG levels

Overall, 12 effect sizes from 11 clinical trials with a total sample size of 457 participants were included in the analysis [ 16 , 18 , 19 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. After combining effect sizes, we found a significant reducing effect of GCE supplementation on FBG levels (WMD: -2.35, 95% CI: − 3.78, − 0.92 mg/dL, P = 0.001) (Fig. 1 ). However, there was a moderate between-study heterogeneity ( I 2 : 46.8, P = 0.03). To detect the sources of between-study heterogeneity, we performed subgroup analyses according to gender (male, female, or both), length of intervention (≥8 vs. < 8 weeks), baseline levels of FBG (≥100 vs. < 100 mg/dL) and participants’ compliance (acceptable, non-acceptable, or unclear) (Table 2 ). From these analyses, we found that gender, baseline levels of FBG and participants’ compliance could explain between-study heterogeneity. In addition, GCE supplementation had a reducing effect on FBG in studies performed on both genders, those with an intervention duration of ≥8 weeks, and those in which participants had a good adherence to the intervention. Findings from the sensitivity analysis revealed that the overall estimate did not depend on a particular study. Based on the Begg’s test and visual inspection of funnel plot (Supplemental Figure 2 A), no evidence of a publication bias was found ( P = 0.21).

Forest plot for the effect of GCE supplementation on FBG levels, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, FBG: fasting blood glucose, CI: confidence interval

In the non-linear dose-response analysis, we found that the association between dosage of CGA and FBG levels was in a non-linear fashion (Supplemental Figure 3 A); such that greater reducing effect of CGA on FBG levels was seen at the dosage of ≥200 mg/day (P non-linearity = 0.03).

The effect of GCE on serum concentrations of insulin

Combining 7 effect sizes from 6 studies [ 18 , 19 , 24 , 25 , 26 , 29 ] that included 347 participants revealed that GCE supplementation resulted in a significant reduction in serum concentrations of insulin (WMD: -0.63, 95% CI: − 1.11, − 0.15 μU/L, P = 0.01) (Fig. 2 ). We observed a moderate between-study heterogeneity ( I 2 : 49.4, P = 0.06). In the subgroup analyses, we observed that between-study heterogeneity could be explained by gender and participants’ compliance. A significant reducing effect of GCE supplementation on serum insulin concentrations was also seen in all subgroups. Based on the sensitivity analysis, no single study influenced the overall estimate. Also, no evidence of a substantial publication bias was found according to the Begg’s test ( P = 0.45) and funnel plot (Supplemental Figure 2 B).

Forest plot for the effect of GCE supplementation on serum insulin concentrations, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, WMD: weighted mean difference, CI: confidence interval

Based on the non-linear dose-response analysis, no significant effect of CGA dosage on serum insulin concentrations was seen (P non-linearity = 0.62) (Supplemental Figure 3 B).

The effect of GCE on serum concentrations of TG

Totally, 12 studies with a total sample size of 642 participants were included for this effect [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ]. Combining 15 effect sizes from these studies revealed no significant effect of GCE supplementation on serum TG concentrations (WMD: -3.17, 95% CI: − 11.82, 5.49 mg/dL, P = 0.47) (Fig. 3 ). However, between-study heterogeneity was significant ( I 2 : 59.1, P = 0.002). Subgroup analyses based on gender and length of follow-up could decrease the between-study heterogeneity. In addition, we found a significant lowering effect of GCE supplementation on serum concentrations of TG in studies performed on both genders. The sensitivity analysis revealed that the exclusion of any particular study did not change the overall estimate. We found no evidence of a substantial publication bias according to the Begg’s test ( P = 0.96) and funnel plot (Supplemental Figure 2 C).

Forest plot for the effect of GCE supplementation on serum TG concentrations, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, TG: triglyceride, WMD: weighted mean difference, CI: confidence interval

In the dose-response analysis, we found a significant non-linear association between CGA dosage and serum TG concentrations; such that dosage of CGA from low levels to 500 mg/day had a significant lowering effect on TG levels (P non-linearity = 0.01), while this beneficial effect was reduced from dosage of 500 mg/day to higher amounts (Supplemental Figure 4 A).

The effect of GCE on serum concentrations of TC

Overall, 16 effect sizes from 13 clinical trials [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ] with a sample size of 662 participants were included in the analysis. Combining these effect sizes, a significant reduction was seen in serum concentrations of TC following GCE supplementation (WMD: -4.51, 95% CI: − 8.39, − 0.64 mg/dL, P = 0.02) (Fig. 4 ) . There was an evidence of moderate between-study heterogeneity ( I 2 : 44.1, P = 0.03). In the subgroup analyses, we found that gender, length of duration, baseline levels of TC and participants’ compliance could explain between-study heterogeneity. Based on these analyses, the effect of GCE supplementation on serum TC concentrations strengthened in studies performed on females and both genders, those with ≥8 weeks’ duration of follow-up and studies that were performed on participants with elevated baseline serum levels of TC (≥200 mg/dL). In the sensitivity analysis, significant association attenuated after exclusion of the study by Heidari et al. [ 19 ] (WMD: -4.11, 95% CI: − 8.61, 0.40 mg/dL, P = 0.07) and the study by Shahmohammadi et al. [ 26 ] (WMD: -3.69, 95% CI: − 7.47, 0.08 mg/dL, P = 0.05). However, this effect was marginally significant. Visual inspection of funnel plot (Supplemental Figure 2 D) and findings from the Begg’s test revealed no evidence of a substantial publication bias ( P = 0.58).

Forest plot for the effect of GCE supplementation on serum TC concentrations, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, TC: total cholesterol, WMD: weighted mean difference, CI: confidence interval

Based on the dose-response analysis, no significant non-linear association was observed between CGA dosage and serum TC concentrations (P non-linearity = 0.15) (Supplemental Figure 4 B).

The effect of GCE on serum concentrations of LDL

Considering 15 effect sizes from 12 studies [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ] which included 642 participants, no significant effect of GCE supplementation on serum concentrations of LDL was found (WMD: -2.02, 95% CI: − 5.58, 1.54 mg/dL, P = 0.26, I 2 : 47.6, P = 0.02) (Fig. 5 ). Subgroup analyses based on gender, duration of follow-up, baseline values of LDL, and participants’ compliance could decrease between-study heterogeneity. From these analyses, we found that GCE supplementation significantly reduced serum LDL concentrations in studies included only female subjects, studies with a follow-up duration of ≥8 weeks, studies that included participants with normal baseline levels of LDL, and those with low or unclear compliance of participants. A sensitivity analysis revealed that the overall effect size was not influenced by a single study. No evidence of a substantial publication bias was seen based on the results from the Begg’s test ( P = 0.40) and funnel plot (Supplemental Figure 2 E).

Forest plot for the effect of GCE supplementation on serum LDL concentrations, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, LDL: low-density lipoprotein, WMD: weighted mean difference, CI: confidence interval

In the dose-response analysis, no significant association was found between CGA dosage and serum levels of LDL (P non-linearity = 0.27) (Supplemental Figure 4 C).

The effect of GCE on serum concentrations of HDL

Totally, 12 studies provided data on the effect of GCE supplementation on serum HDL concentrations [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 26 , 27 , 28 , 29 ]. Combining 15 effect sizes from these studies revealed no significant effect of GCE supplementation on HDL levels (WMD: 1.08, 95% CI: − 0.22, 2.38 mg/dL, P = 0.10) (Fig. 6 ). A marginally significant between-study heterogeneity was seen in this regard ( I 2 : 47.6, P = 0.02). In the subgroup analyses, we found that gender, length of follow-up, baseline levels of HDL and participants’ compliance were potential sources of heterogeneity. In addition, GCE supplementation resulted in a significant increase in serum HDL concentrations in trials included only female subjects, studies with ≥8 weeks of intervention duration, studies that were performed on participants with low levels of baseline serum HDL and studies with low or unclear adherence of participants to intervention. The sensitivity analysis revealed that the overall estimate depended on two studies [ 18 , 26 ]. When we excluded these studies, Shahmohammadi et al. (WMD: 1.32, 95% CI: 0.03, 2.62 mg/dL, P = 0.04) and Fukagawa et al. studies (WMD: 1.44, 95% CI: 0.23, 2.64 mg/dL, P = 0.02), a significant increasing effect of GCE supplementation on serum HDL concentrations was observed. No evidence of a substantial publication bias was seen according to the Begg’s test ( P = 0.80) and funnel plot (Supplemental Figure 2 F).

Forest plot for the effect of GCE supplementation on serum HDL concentrations, expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from random-effects analysis. GCE: green coffee extract, HDL: high-density lipoprotein, WMD: weighted mean difference, CI: confidence interval

In the dose-response analysis, we found a significant non-linear association between CGA dosage and serum concentrations of HDL (P non-linearity = 0.01); such that from dosage of 100 mg/day to higher levels, CGA administration had an increasing effect on serum HDL concentrations (Supplemental Figure 4 D).

The role of coffee consumption in the risk of cardiovascular diseases has been debated for many years. Recent meta-analyses of prospective studies showed no potential health risk associated with the coffee intake [ 42 , 43 ] even when heavily consumed [ 44 ]. Also, an umbrella review of meta-analyses revealed the protective effects of coffee consumption against cardiovascular risk factors [ 45 ]. Unlike observational studies, considerable controversy exists among clinical trials. In the current study, we summarized evidence from clinical trials investigating the effect of GCE supplementation on lipid profile and some glycemic indices. We found that GCE supplementation significantly reduced FBG and insulin levels. Considering the lipid profile, GCE supplementation resulted in a significant decrease in TC concentrations, but results from other lipid measures were not significant. However, GCE supplementation improved serum levels of TG, LDL, and HDL in some subgroups of studies. Also, in the non-linear dose-response analyses, we found that the associations between CGA dosage and serum levels of FBS, TG, and HDL were in a non-linear fashion.

We found a significant reduction in both serum levels of FBG and insulin following GCE supplementation. In line with our findings, Morvaridi et al. reported a beneficial effect of green coffee consumption on glycemic indices and cardio-metabolic risk factors in adults [ 46 ]. In contrast with our findings, in a meta-analysis, Kondo et al. reported no significant effect of caffeinated/decaffeinated coffee consumption on FBS and insulin levels [ 47 ]. The observed controversy in this regard might be due to the use of different types of coffee across previous clinical trials. Green coffee contains a higher amount of CGA compared with other types of coffee. It seems that the anti-diabetic effect of green coffee is attributed to its CGA content. As seen in the dose-response analysis, the stronger reducing effect of GCE on FBG was observed at CGA dosage of 200 mg/d or more. CGA increases peripheral glucose disposal through activating AMP-activated protein kinase (AMPK) [ 48 ]. It also reduces glucose production by gluconeogenesis and glycogenolysis through inhibiting glucose-6-phosphatase [ 49 ]. Moreover, increased serum concentrations of adiponectin, a protein hormone released from adipose tissue that modulates glucose regulation and fatty acid oxidation, may play a role in the metabolic effect of CGA [ 50 ]. Reducing blood glucose through the mentioned pathways can also decrease insulin levels.

In the overall meta-analysis of the effect of GCE on lipid profile, we found a reducing effect only on serum levels of TC. In agreement with our findings, a prospective cohort study indicated a significant inverse association between coffee consumption, particularly green coffee, and TC levels [ 51 ]. Also, in an experimental study, GCE administration could significantly reduce TC levels [ 52 ]. In contrast, available findings on the effects of other types of coffee on lipid profile are conflicting [ 30 ]. Different findings might be explained by different processing methods used for preparation of coffee. In a systematic review, Penson et al. reported that the type of coffee and the methods of preparation are important for the effect of coffee consumption on serum levels of lipoproteins [ 53 ]. In addition, different duration of intervention, recruiting participants with different health conditions and different quality of clinical trials are other reasons for the observed discrepancy across clinical trials investigating the effects of coffee consumption on TC levels.

Although the overall analysis did not show significant effects of GCE supplementation on serum levels of LDL and HDL, we found favorable effects in studies that recruited female subjects. Further, the TC-lowering effect increased in studies conducted on either gender or female subjects. The analysis also showed a significant reducing effect of GCE on serum levels of TG and FBG among studies that included both sexes. It seems that sex may mediate the effect of GCE on lipid profile with a stronger effect observed in women. It has been shown that CGA is more durable in women than men and therefore, had a longer effect on women than men [ 54 ]. Also, the sex differences may be mediated by changes in steroid hormone levels [ 55 ].

In our meta-analysis, the beneficial effects of GCE supplementation were mostly observed in RCTs with a long duration of the intervention (≥8 weeks). It is consistent with the results from the previous meta-analysis on green coffee consumption in which a longer duration (> 8 weeks) was more effective on lipid profile [ 56 ]. In a network meta-analysis, Kondo et al. concluded that clinical trials with a longer duration of intervention can better clarify the potential effects of coffee [ 47 ]. Thus, green coffee consumption should be long enough to improve the lipid profile.

Dose-response analysis demonstrated a significant increment in serum levels of HDL from CGA dosage of 100 mg/day to higher amounts. Moreover, we found a significant non-linear association between CGA dosage and serum TG concentrations. However, the TG-lowering effect of CGA was decreased at a dosage of 500 mg/d and over. The effect of green coffee on lipid profile was also dose-dependent in earlier meta-analyses of RCTs [ 56 , 57 ]. Therefore, the dosage of CGA is a potential moderator for the beneficial effect of GCE on lipid profile. CGA may exert its lipid-lowering effects through inhibition of the lipids absorption and the formation of cholesterol micelles. Also, CGA is involved in modifying hepatic metabolism of cholesterol and fatty acids by inhibiting pancreatic lipase and hydroxymethyl glutaryl Co-A reductase and increasing the activity of fatty acid beta-oxidation and the expression of peroxisome proliferator-activated receptor-alpha in the liver [ 13 , 58 ]. Based on our finding, however, higher dosages of more than 500 mg/d CGA is not recommended. Of note that higher intake of CGA may elevate homocysteine levels, a risk factor for cardiovascular disease, and stimulate the release of adrenaline generating several effects on the cardiovascular system including increased blood pressure and reduced insulin sensitivity [ 50 , 59 , 60 ].

The current meta-analysis was the first to summarize available findings on the effects of GCE supplementation on glycemic and lipid profiles. The selected studies were from different countries which increase the generalization of findings to the various ethnic groups. Other strengths of this meta-analysis were the inclusion of all clinical trials written in all languages, lack of publication bias, and moderate-to-high quality of the most included studies. However, some limitations should be considered when interpreting our findings. These limitations include the lack of evaluation of participants’ compliance in a limited number of RCTs, the lack of controlling for baseline values of glycemic and lipid measures in some others, short duration of intervention in some trials, and different health conditions of participants across included studies. Also, we could not find the effect of GCE supplementation on other glycemic indices such as HbA1c due to limited number of studies.

GCE supplementation had favorable effects on glycemic indices including FBG and insulin levels. In terms of lipid profile, GCE supplementation led to a significant reduction in serum TC, particularly in individuals with elevated levels of TC. This suggests GCE as a promising antihyperlipidemic agent since some patients do not achieve cholesterol reduction goals or cannot tolerate statins due to adverse effects [ 61 ]. We also found a significant favorable effect of GCE on serum levels of TG, LDL, and HDL in some subgroups. The effect was more prominent in women and studies with a long duration of intervention. Further studies are required to find the effect of GCE supplementation on patient-reported outcomes including quality of life, as well as the effect of genetic polymorphisms on the pharmacokinetics of CGA to explain the interindividual variability.

Availability of data and materials

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

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Acknowledgements

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This study was supported by the Gerash University of Medical Sciences, Gerash, Iran.

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Omid Asbaghi

Department of Nutrition, School of Allied Medical Sciences, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

Mehdi Sadeghian

Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran

Morteza Nasiri

Department of Operating Room Nursing, School of Nursing and Midwifery, Shiraz University of Medical Sciences, Shiraz, Iran

Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Mahmoud Khodadost

Department of Epidemiology, School of Public Health, Iran University of Medical Sciences, Tehran, Iran

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Gerash University of Medical Sciences, Gerash, Iran

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OA, MS, MN and OS contributed in systematic search and data extraction. MK, AP, AS and OS contributed in statistical analyses and data interpretation. OS, BP and MS contributes in manuscript drafting and data interpretation. All authors approved the final manuscript for submission.

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Additional file 1: supplemental table 1.

. Results of risk of bias assessment for clinical trials included in the current meta-analysis on the effects of GCE supplementation on glycemic and lipid measures 1 . Supplemental Figure 1. Flow diagram of study selection. Supplemental Figure 2. Funnel plots for the effect of GCE supplementation on serum levels of FBG (A), insulin (B), TG (C), TC (D), LDL (E), and HDL (F). WMD: weighted mean difference, FBG: fasting blood glucose, TG: triglyceride, LDL: low-density lipoprotein, HDL: high-density lipoprotein. Supplemental Figure 3 . Non-linear dose-response effects of CGA dosage (mg/d) on (A) FBG and (B) serum levels of insulin. The 95% CI is demonstrated in the shaded regions. CGA: chlorogenic acid, FBG: fasting blood glucose. Supplemental Figure4 . Non-linear dose-response effects of CGA dosage (mg/d) on serum concentrations of (A) TG, (B) TC, (C) LDL, and (D) HDL. The 95% CI is demonstrated in the shaded regions. CGA: chlorogenic acid, TG: triglycerides, TC: total cholesterol, LDL: low-density lipoprotein, HDL: high-density lipoprotein

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Asbaghi, O., Sadeghian, M., Nasiri, M. et al. The effects of green coffee extract supplementation on glycemic indices and lipid profile in adults: a systematic review and dose-response meta-analysis of clinical trials. Nutr J 19 , 71 (2020). https://doi.org/10.1186/s12937-020-00587-z

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DOI : https://doi.org/10.1186/s12937-020-00587-z

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Journal of Evidence-Based Integrative Medicine

Green Coffee for Pharmacological Weight Loss

Introduction, data sources, selection, and extraction, data synthesis, ethical approval, declaration of conflicting interests, cite article, share options, information, rights and permissions, metrics and citations, figures and tables.

	Over the Counter	Prescription
Orlistat (Alli, Xenical)	X	X
Phentermine (Adipex)		X
Diethylpropion (Tenuate)		X
Phentermine/Topiramate (Qsymia)		X
Lorcaserin (Belviq)		X

	Study Design	Duration	Primary Endpoint	Secondary Endpoints
FDA Recommendations	Randomized, double-blind, placebo-controlled; >3000 receive active medication, >1500 receive placebo	1 year	Amount of weight loss; proportion of patients losing 5% of baseline weight versus placebo	Metabolic parameters
Vinson et al	Randomized, double-blind, placebo-controlled, crossover; 16 patients	22 weeks	Weight, body mass index, percent body fat	Changes in blood pressure and heart rate
Ayton Global Research	Randomized, double-blind; 62 volunteers	4 weeks	Weight	Waist, bust, and hip size
Dellalibera et al	Randomized, placebo-controlled; 50 volunteers	60 days	Not identified	Not identified
Thom et al	Randomized; 30 volunteers	12 weeks	Not identified	Not identified
	100 female volunteers	Not identified	Weight	Not identified

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Green Coffee

Green coffee beans are raw, unroasted coffee beans. The roasting process seems to destroy some of the healthy, natural chemicals in the beans. Because of media attention, green coffee has become a popular supplement for weight loss.

Why do people take green coffee?

Some research shows green coffee may help with weight loss. A few small studies found that people taking green coffee lost 3 to 5 pounds more than people who weren't. Green coffee may act by lowering blood sugar and blocking fat buildup.

Green coffee also seems to help lower high blood pressure in some people. One small study in people with mild high blood pressure showed benefit over the placebo .

Optimal doses of green coffee have not been set for either condition. Quality and active ingredients in supplements may vary widely from maker to maker. This makes it hard to set a standard dose. Ask your doctor for advice.

Can you get green coffee naturally from foods?

Green coffee comes from the same beans people use for brewing coffee. The only difference is that the coffee beans are unroasted.

What are the risks?

Tell your doctor about any supplements you're taking, even if they're natural. That way, your doctor can check on any potential side effects or interactions with medications .

Side effects. Green coffee seems to cause few side effects. The caffeine in green coffee -- just like the caffeine in brewed coffee -- can cause symptoms that include:

Upset stomach

Risks. Because of its caffeine , extremely high doses of green coffee could be dangerous. Caffeine may not be good for people with conditions such as:

High blood pressure
Irritable bowel syndrome
Osteoporosis
Bleeding disorders

Talk to your doctor if you have any medical conditions before using a green coffee supplement. Given the lack of evidence about its safety, doctors don't recommend green coffee for children or for women who are pregnant or breastfeeding .

Interactions. If you take any medicines regularly, talk to your doctor before you start using green coffee supplements . Green coffee interacts with many medicines. Some of these include stimulants, blood thinners , and medicines for:

Heart problems
Lung diseases
Schizophrenia

Don't take green coffee along with herbal stimulants or other supplements with caffeine.

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The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials

Affiliation.

1 Complementary Medicine, Peninsula Medical School, University of Exeter, 25 Victoria Park Road, Exeter EX2 4NT, UK.
PMID: 20871849
PMCID: PMC2943088
DOI: 10.1155/2011/382852

The purpose of this paper is to assess the efficacy of green coffee extract (GCE) as a weight loss supplement, using data from human clinical trials. Electronic and nonelectronic searches were conducted to identify relevant articles, with no restrictions in time or language. Two independent reviewers extracted the data and assessed the methodological quality of included studies. Five eligible trials were identified, and three of these were included. All studies were associated with a high risk of bias. The meta-analytic result reveals a significant difference in body weight in GCE compared with placebo (mean difference: -2.47 kg; 95%CI: -4.23, -0.72). The magnitude of the effect is moderate, and there is significant heterogeneity amongst the studies. It is concluded that the results from these trials are promising, but the studies are all of poor methodological quality. More rigorous trials are needed to assess the usefulness of GCE as a weight loss tool.

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Green Coffee Extract is most often used for .

Green Coffee Extract

Green Coffee Extract is a concentrated source of dietary Chlorogenic Acid and is currently being used for heart health and fat loss as a supplement; it seems weakly to moderately effective on these parameters.

Last Updated: September 28, 2022

Sources and Summary

Composition

Pharmacology

Cardiovascular Health

Blood Pressure

Interactions with Glucose Metabolism

Interventions

Interactions with Fat Mass

Interactions with Oxidation

Glutathione

Safety and Toxicity

Chlorogenic Acid compounds, which are small phenolics bound to Quinic Acid; commonly seen as the main active component of Green Coffee Extract [1] with about 7-12g per 100g before processing and up to 42.2% of all phenolics. [2] The major chlorogenic acids appear to be dicaffeoylquinic (3,4-, 3,5-, and 4,5) and all caffeoyl, feruloyl, and p-coumaroyl quinic acids at 3-, 4-, and 5- positions, [1] although caffeoylquinic acids are the major ones. There does not appear to be much difference in the quantities of isomers relative to each other [1]
Epicatechin (21.6% of phenolic content) and Catechin (2.2%) [2]
Isochlorogenic acids I (5.7%), II (19.3%), and III (4.4%); all in reference to total phenolic content [2]
Ferulic Acid at 1% Phenolics [2] (although Chlorogenic acids may metabolize into Ferulic acid after ingestion) [3]
Caffeoyltryptophan (26.25umol/g) [1]
Rutin at 2.2% of total phenolics (form of Quercetin ) [3]
Terpene esters Kahweol palmitate and Cafestol palmitate (as well as both Kahweol and Cafestol) [4]

Roasting green coffee beans may induce the Chlorogenic acids to form lactone structures, [5] and chlorogenic acid is detectable in plasma regardless of roasting [6] or raw extracts. [1]

After ingestion of 400mg decaffeinated Green Coffee Bean extract (170mg Chlorogenic acids), absorption rates of Chlorogenic acids and phenolics appear to exceed 30% suggesting high absorption rates. [1]

After oral ingestion of 5-caffeoylquinic acid in isolation to rats, there is a detectable level of plasma Caffeic Acid and Ferulic Acid while the blood levels of 5-caffeoylquinic acid itself were below detectable levels even after 200mg/kg; suggestive of rapid metabolism. [3] Caffeic Acid and Ferulic acid peak at 6 and 9 hours post ingestion of 200mg/kg 5-Caffeoylquinic acid reaching 179ng/mL and 174ng/mL respectively, with a detectable level observed up until 24 hours. [3] Caffeoylquinic acids in general consist of 44% of serum phenolic metabolites in humans (31.3, 7.5, and 5.2% for 3-, 4-, and 5- respectively) and 55% of the Chlorogenic Acids, with dicaffeoylquinic acids and ferulic acid comprising most of the rest. [1]

The one human study assessing 400mg Green Coffee Bean extract (170mg Chlorogenic Acids; CGAs) noted high interindividual variability, although the T max of most phenolics was in the range of 3-4 hours (2.5 for p-coumaric acid) and, after 170mg Chlorogenic acids, the C max of total CGAs was 14.8+/-11.7umol/L). [1]

In rats, 180-720mg/kg Green Coffee Extract (28% Chlorogenic Acid) is able to acutely reduce blood pressure in spontaneously hypertensive rats over 12 hours in a dose-dependent manner (6.8-12.5%), with the two higher doses still being significant at 24 hours (5.7-11.1%); [3] a reduction of heart rate was also noted, only occurred at the highest dose in control group (Wistar Kyoto rats), and was thought to be due to the 5-caffeoylquinic acid content, which degrades into Ferulic Acid (active compount). [3] A component of Green Coffee Extract, ferulic acid, was then shown to enhance the activity of tested blood pressure lowering medications acutely (Nicardipine, Captopril, and Prazosin). [3]

One study using Green Coffee Extract (480mg) with a 30.9% Chlorogenic Acid content (140mg) daily for 12 weeks in men with essential hypertension noted reductions in heart rate (8%), diastolic blood pressure (7%), and systolic blood pressure (8%); all benefits appears to occur at week 4 and were maintained for 12 weeks, and trended towards baseline after 2 weeks of cessation. [7] Another study (20 otherwise healthy men, but with impaired vasoreactivity and blood flow) has also noted improvements to blood health in response to Green Coffee extract (140mg Chlorogenic acids via liquid test drink) for 4 months was able to increase the reactive hyperemia ratio in response to strain gauge plethysmogram () by 69% when placebo experienced a nonsignificant decrease; a trend to decrease blood pressure was noted (from 115/69 to 110/63) but this was not statistically significant. [8]

Low doses have been noted to reduce blood pressure in one study of prehypertensive persons; may be temporary, and possibly works via the Chlorogenic Acid content breaking down into Ferulic Acid. Has also been noted to increase vasoreactivity,

Acutely, 10g of Chlorogenic Acid (CGA) enriched Green Coffee (10g of coffee powder, at 4-4.5% CGA totalling 400-450mg CGA) is able to reduce the Area Under Curve (AUC) of glucose in response to 25g sucrose by 7% over 120 minutes post consumption. [9]

A study conducted in persons with prehypertension that also measured blood glucose (as part of a safety panel) noted that in persons with elevated but not prediabetic levels of blood glucose (89-109mg/dL) failed to note any significant reductions over 12 weeks using 480mg of Green Coffee Extract (30.9%, or 140mg, of Chlorogenic Acid). [7]

In mice, 0.5-1% of the diet as Green Coffee bean extract is able to reduce body weight gain in mice while both isolated caffeine and chlorogenic acid showed a trend to do so. [10] The authors noted that Chlorogenic Acids could reduce triglyceride accumulation in the liver (caffeine ineffective) and caffeine could reduce circulating triglycerides after an olive oil test (feeding olive oil to mice acutely; chlorogenic acid ineffective) while the metabolite of chlorogenic acid, ferulic acid, increased fatty acid oxidation in the liver. [10]

A Meta-Analysis [11] conducted on the topic assessing noted that out of 5 human trials on Green Coffee Extract (GCE) that only three measured weight as a primary endpoint and that these trials had a large degree of heterogeneity and high risk of bias (with only one being indexed in Medline, [9] and two associated with for-profit companies of which only one can be located online [12] and one downloadable pdf [13] ); [11] the average weight loss was 2.47kg according to this meta-analysis. The one trial indexed in Medline noted that weight loss over 12 weeks in obese persons (When 11g of Green Coffee giving 440-495mg Chlorogenic Acid daily) reached 5.4+/-0.6kg (with control coffee reaching 1.7+/-0.9kg; significantly less) and appeared to reduce fat mass by 3.6%, which comprised about 80% of total weight loss. [9] Only one other study prior to the conductance of this meta-analysis has assessed weight loss in persons with GCE, and this study that measured weight (not as the main study parameter) noted that 0.48g of GCE for 12 weeks (conferring 140mg Chlorogenic Acid ) failed to reduce weight, [7] while studies conducted afterwards (and thus excluded) note that in overweight (n=16) adults given 700mg (2 doses of 350mg) Green Coffee Extract at 45.9% Chlorogenic Acid noted weight loss; [14] specifically, all subjects underwent periods of 350mg, 700mg, or placebo for 8 weeks each in randomization noted that weight loss over time was associated with the periods of Green Coffee Extract. [14]

Limited evidence to support the notion that Chlorogenic acids and their vessel, Green Coffee Extract, induce weight loss. That being said, despite numerous studies having potential conflicts of interest other independent studies also note weight loss may occur to a small degree in overweight subjects (lean subjects not yet tested)

Glutatione, an antioxidant enzyme, is induced in activity by the diterpene ester Kahweol palmitate and its monoacetate Kahweol; Cafestol can induce activity as well, although the palmitate bound to it reduces activity. [4] 20% Green Coffee Extract to the diet of rats for 12 days appears to increase hepatic glutathione activity 5-fold relative to control (with intestinal mucosa having a smaller spike in activity), which was mostly replicated with 2.5mg of either diterpene in isolation. [4]

Green coffee extracts, supplemental or food products, may cause a respiratory response indicative of allergens. [15] Occupational type I allergies have been noted to be associated with Green Coffee dust, which may be due to the presence of a 'Cof A 1' allergin. [16] This allergin is different than that of castor beans (both of which are known to induce occupational allergies in those who handle them) [17] and appears to be present in the plants Coffea canephora , Coffea Arabica , and Coffea liberica . [16]

It is possible to be allergic to Green Coffee Extracts, which appears to be related to an allergin that may also be present in common Coffee products

^ Farah A, Monteiro M, Donangelo CM, Lafay S Chlorogenic acids from green coffee extract are highly bioavailable in humans J Nutr . ( 2008 Dec )
^ Phenolic compounds in coffee pulp: Quantitative determination by HPLC
^ Suzuki A, Kagawa D, Ochiai R, Tokimitsu I, Saito I Green coffee bean extract and its metabolites have a hypotensive effect in spontaneously hypertensive rats Hypertens Res . ( 2002 Jan )
^ Lam LK, Sparnins VL, Wattenberg LW Isolation and identification of kahweol palmitate and cafestol palmitate as active constituents of green coffee beans that enhance glutathione S-transferase activity in the mouse Cancer Res . ( 1982 Apr )
^ Farah A, de Paulis T, Trugo LC, Martin PR Effect of roasting on the formation of chlorogenic acid lactones in coffee J Agric Food Chem . ( 2005 Mar 9 )
^ Chlorogenic Acid Compounds from Coffee Are Differentially Absorbed and Metabolized in Humans
^ Watanabe T, Arai Y, Mitsui Y, Kusaura T, Okawa W, Kajihara Y, Saito I The blood pressure-lowering effect and safety of chlorogenic acid from green coffee bean extract in essential hypertension Clin Exp Hypertens . ( 2006 Jul )
^ Ochiai R, Jokura H, Suzuki A, Tokimitsu I, Ohishi M, Komai N, Rakugi H, Ogihara T Green coffee bean extract improves human vasoreactivity Hypertens Res . ( 2004 Oct )
^ Thom E The effect of chlorogenic acid enriched coffee on glucose absorption in healthy volunteers and its effect on body mass when used long-term in overweight and obese people J Int Med Res . ( 2007 Nov-Dec )
^ Shimoda H, Seki E, Aitani M Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice BMC Complement Altern Med . ( 2006 Mar 17 )
^ Onakpoya I, Terry R, Ernst E The use of green coffee extract as a weight loss supplement: a systematic review and meta-analysis of randomised clinical trials Gastroenterol Res Pract . ( 2011 )
^ The Effect of Chlorogenic Acid Enriched Coffee (Coffee Shape) on Weight When Used in Overweight People
^ Svetol®, green coffee extract, induces weight loss and increases the lean to fat mass ratio in volunteers with overweight problem
^ Vinson JA, Burnham BR, Nagendran MV Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects Diabetes Metab Syndr Obes . ( 2012 )
^ Zuskin E, Kanceljak B, Skurić Z, Butković D Bronchial reactivity in green coffee exposure Br J Ind Med . ( 1985 Jun )
^ Manavski N, Peters U, Brettschneider R, Oldenburg M, Baur X, Bittner C Cof a 1: identification, expression and immunoreactivity of the first coffee allergen Int Arch Allergy Immunol . ( 2012 )
^ Lehrer SB, Karr RM, Salvaggio JE Analysis of green coffee bean and castor bean allergens using RAST inhibition Clin Allergy . ( 1981 Jul )

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The Use of Green Coffee Extract as a Weight Loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials

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Nestlé on developing future-proof coffee

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Global coffee production is set to plummet by 2050 if current predictions are correct. GCR discovers how Nestlé is using agricultural science to develop new varietals that can withstand the shifting climate.

As some of the world’s largest coffee roasters, Nestlé has skin in the game when it comes to the future of the coffee-farming industry. Each year, the parent company purchases around 13 million bags of green coffee from 20 countries for its brands Nescafé, Nespresso, and Starbucks Coffee at Home, sourcing from and working alongside hundreds of thousands of smallholder coffee farmers. It’s presence is so big that it reports one in every seven cups of coffee consumed in the world is Nescafé.

Despite global demand for coffee continuing to rise, the future of these farmers, Nestlé’s coffee brands, and the industry at large is under threat due to the effects of climate change. According to a 2022 Intergovernmental Panel on Climate Change (IPCC) report, by 2050 the land suitable to grow Arabica coffee could be reduced by up to 50 per cent. What’s more, it’s not just the future of coffee that’s at stake: producers around the world are already feeling the effects of our warming climate.

To future-proof its coffee businesses, Nestlé has turned to agricultural science to look for sustainable solutions that can mitigate impacts on the supply chain and ensure coffee is available to all those who want to drink it. In 2023, it opened the Nestlé Institute of Agricultural Sciences in Switzerland to help progress its work in advancing sustainable food systems.

“Our goal is to identify the most promising solutions to promote the production of nutritious raw materials while minimising their environmental impact. We take a holistic approach and look at several factors including impact on yield, carbon footprint, food safety, and cost, as well as the viability of scale-up,” says Jeroen Dijkman, Head of Nestlé Institute of Agricultural Sciences.

One such project has been the development of a new, high-yielding Arabica coffee variant, which Nestlé’s team of scientists believe is an important step towards creating resilient supply chains.

“The main challenges for coffee growing today are low yields, pest and diseases, and adaptation to a changing climate,” says Juan Carlos Herrera, Senior Coffee Breeder at Nestlé Research & Development.

“Nestlé works on all these aspects for the selection of new, high performing varieties.”

The process of creating a new coffee plant variety starts in the lab, where an interdisciplinary team of research and development specialists, scientists, and agronomists explores the potential of existing genetic resources.

“The process starts with harnessing the natural genetic variety of coffee trees, making conventional crossings between trees harbouring the desired traits. For example, this could be crossing a variety with high yield that is susceptible to diseases with a variety with lower yield that is disease resistant,” says Herrera.

“After the crossing follows a selection process among the progenies to identify the trees carrying the combined desired traits.”

The traits the Nestlé team are focusing on are high yield, resistance to diseases such as coffee leaf rust, and resistance to drought, all of which can help coffee plants thrive in a more unpredictable climate. They also look for high-quality beans and sensory attributes.

“The selected trees are then tested in experimental plots, first at small scale on our experimental farms and later at larger scale in producing countries. Only the best performing trees will then be selected for local registration and distribution to farmers,” he says.

Trialling the trees in different producing countries, each with its own unique climate, elevation, and farming traditions, enables the scientists and agronomists to monitor the trees’ stability in different environments. This is another contributing factor to the success of the tree and whether it will be rolled out.

Following their most recent research project, Herrera and the Nestlé team have developed Star 4, a novel high-yielding Arabica coffee variety selected in Brazil for its resilience. They believe it shows a good cup quality close to Brazilian coffees, but with reduced environmental impact and higher yields.

“Star 4 was selected for its overall robustness and results in field trials where various key performance indicators were measured, including yield. The preliminary results are promising and are to be confirmed when we deploy the variety at a larger scale,” he says.

The hope is that Star 4 will not only be more resilient to the changing climate but will also contribute to the reduction of carbon emissions in the coffee industry. For example, if it is successful, the higher yield of the variety in comparison to traditional Arabica plants will reduce its carbon footprint because using the same fertilisation inputs could produce more coffee.

“Our calculations show a 50 per cent increase in yield will result in a 30 per cent reduction of the carbon footprint of green coffee after harvest,” says Herrera.

Growing coffee varieties such as Star 4 with increased resistance to disease requires fewer pesticides, which also has a lower impact on the environment. Furthermore, varieties that are more tolerant to drought require less water and reduced irrigation during the dry season.

While Star 4 was selected for Brazilian conditions, it could also perform well in other coffee producing countries. However, Herrera stresses this might not be the case.

“It is difficult to extrapolate results in one region or country to others, mostly because the performance of a variety depends on variable factors such as climate, soil, presence of diseases, and farming practices,” he says.

According to Nestlé, reduced green- house-gas emissions from higher coffee yields are also attributed to improved plant productivity and farming methods.

“Optimising cultivation practices remains vital as they are the primary factor contributing to the environmental impact of a cup of coffee,” says Marcelo Burity, Nestlé Head of Green Coffee Development.

The company’s drive to develop new, resistant coffee varieties goes hand in hand with its focus on regenerative agriculture, reducing greenhouse gas emissions, and improving farmers’ livelihoods. As part of its Nescafé Plan 2030, the company has pledged to make coffee farming more sustainable and is investing more than CHF 1 billion (around US$1.1 billion) in the project.

“Beyond its work on plants, Nestlé is engaged in agronomy and farming practices to reduce the environmental impact of coffee culture,” says Herrera.

“In 2023, our teams reached 277,000 farmers in 27 origins. The coffee growers took part in training on the principles of regenerative agriculture and more than 21 million coffee plantlets were distributed to support renovation of their coffee farms. They also planted three million forest and fruit trees to help increase local biodiversity and build the natural resilience of their farms.”

One of the company’s ultimate goals within this plan is to achieve 100 per cent sustainably sourced coffee by 2025, an increase from 75 per cent achieved in 2020. According to Nescafé, responsible sourcing means: “making sure our coffee meets sustainability standards and that programs are checked by external bodies to bring benefits throughout the value chain and support the future supply of higher quality coffee”.

This article was first published in the September/October 2024 edition of Global Coffee Report. Read more HERE .

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The surprising science of coffee and its effect on both body and mind

The latest research on caffeine reveals why coffee and decaf can be so good for your health, but energy drinks can be lethal

By Jasmin Fox-Skelly

20 August 2024

Illustration showing three people doing different activities all drinking coffee

“I only drink coffee on days ending in y,” so the saying goes. If this mantra applies to you, welcome to the club. Coffee’s best-known component, caffeine , is estimated to be the most widely used psychoactive drug in the world, with billions of people consuming it every day. But unlike other addictive substances, it is largely unregulated, and nobody would flinch at the idea that you might struggle to function without it from the moment you wake up.

Coffee lovers might be on to something, with a slew of studies showing that, taken in the right way, caffeine can improve many things, not least your cognitive abilities and alertness. What’s more, your pursuit of a Java pick-me-up may bring a host of related health benefits . Yet not all sources of caffeine are viewed equally. In recent months, its health risks, especially when in energy drinks, have been in the spotlight again. In June, the UK Labour party, which now forms the country’s government, pledged to ban the sale of these drinks to children under 16 due to their “dangerously high” caffeine content. This comes hot on the heels of a comprehensive report called The Dark Side of Energy Drinks , which documents cases of people who ended up with severe health issues after consuming them.

How bad is vaping for your health? We’re finally getting answers

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A cautionary tale for Starbucks: Green Mountain Coffee’s founder spills the beans on how it became ‘just another coffee company’

Robert Stiller is the founder of Green Mountain Coffee and the author of Better and Better: Creating a Culture of Purpose, Excellence, and Transformative Human Engagement.

When it came time to choose a successor at Green Mountain, my mental game was off when I most needed it to be on. I had not developed a clear vision of what a successful transition would look like, despite the visualization and meditation skills I had cultivated for years. I didn’t do enough to understand my successor’s way of thinking, help him understand mine, and plan how we could work as a team. I failed to consider how much a new leader could change our company culture and alter the course we were on—which I firmly believed was the right one.

But Green Mountain was growing fast, and I had concerns about running such a big company and managing the workload that came with it. We were adding board members who had leadership experience at companies much larger than us. Had I been more mindful, I would have spent more time and creativity finding a solution that was true to my values, that allowed Green Mountain to continue to thrive and to show the world how a business can drive positive change. I should have read books about the keys to a successful succession—or even just looked for advice online. I should have brought the same curiosity and hunger for research that guided me when I originally bought the company.

Leadership succession is one of the biggest challenges in running a business, and it’s a common one. Typically, somewhere between 10 and 15% of companies replace their CEOs each year, and an estimated one-third to one-half of new chief executives fail within their first 18 months . CEOs taking over from founder-CEOs face an especially tough road: On average, they have shorter tenures and worse financial performance . I think founders tend to have a deeper, longer-term view of an organization, as well as a persistence to make things work that is different from the mindset of a professional CEO. And because founders have such a powerful influence on organizational culture, their departure can be particularly disorienting.

The problem with handpicked successors

There’s no shortage of cautionary tales. When former General Electric executive Robert Nardelli became CEO at the Home Depot , succeeding founder-CEO Bernard Marcus, he dramatically overhauled the company, replacing an entrepreneurial culture of innovative product design with one relentlessly focused on cost-cutting. There are also examples of founder-CEOs who retired—only to come back and “right the ship” when their successor fumbled, such as Steve Jobs at Apple or Howard Schultz at Starbucks . Then, there are stories that fall somewhere in between: My friends Ben and Jerry, the founders of the fabled ice cream company, had to try out a couple of CEOs before finding a long-term fit.

My successor, Larry Blanford, was personable and well-liked by many Green Mountain employees. But looking back, I wonder if he was really the best choice to lead the organization, arriving at a time when the company was already in transition. Once he had taken over as the new CEO, I started to worry that his leadership style—which I considered more “top-down” than my own—could put the brakes on innovation and engagement across the company.

Larry recognized many core Green Mountain strengths. As he told me and others at the time, “It’s like being handed the keys to a high-performance sports car.” But I didn’t do as much as I could have to help him understand what made the car run so well and the work that went into maintaining it.

I underestimated the importance and the challenge of transmitting the essence of a unique culture like Green Mountain’s to someone who was coming in from the outside. And I could have worked harder to cultivate a board of directors that was solidly aligned with the way I had grown the company, that believed in our social and environmental mission and in honoring our commitments to stakeholders across the organization.

Green Mountain’s biggest competitive advantage had long been our ability to leverage the collective intelligence of the organization to grow and improve. Yet when it came to deciding who should run the company after me, I didn’t make my usual effort to hear everyone’s opinions. Many people questioned what I was doing, but I didn’t listen to them. I neglected to value our diverse stakeholders in the succession process and to think hard enough about how my decision would affect them, too.

I made my decision to hire Larry on intuition. I was a little burned out, and he was an experienced leader who was, at the moment, between jobs. I thought it would make my life simpler to work with him to deliver on the plans and strategy that we’d laid out. In practice, I should have known this would require detailed communication—and I did not think about what could go wrong without that communication. Had I imagined that Larry would take the company on such a different path from what I had set out, I would not have hired him. Had Larry been given a clearer sense of what I was looking for, perhaps he would not have taken the job, either.

How a company loses its culture

When I handed over the reins in 2007, Green Mountain was firing on all cylinders. So much so that it was hard to imagine anything stopping our momentum. At the end of 2006, our sales had hit a 40% growth rate. We were on track to be a billion-dollar business in a few years, with Fortune listing us as one of the fastest-growing small companies in the United States. The same year, our stock was added to the Russell 2000 Index. We had surpassed the $1 million mark in our 5% donations to social and environmental initiatives. In 2005, we’d become 100% carbon-neutral and published our first corporate responsibility report. We had clear strategies for immediate and long-term growth. Why not relax a little and let someone else handle the details of execution?

While Bill Davis later told me that he and other board members were surprised at my suggestion, they considered it. In spring 2007, we had recently brought in a new board member, Mike Mardy, who had been executive VP and CFO of the luggage maker TUMI. Larry brought similar big-company experience, which we needed at the time. After interviewing Larry, they supported the decision to hire him.

Research shows that boards will often defer to long-serving, revered CEOs in their choice of a successor—holding back on reasonable questions and concerns. According to an analysis of corporate boards by leadership advisory firm ghSMART, in almost all failed CEO successions, there are one or more board members who are uneasy about the chosen candidate, but who for some reason hesitate to contradict the consensus or feel that they are not fully heard.

Candidates who are handpicked by an outgoing CEO more often than not disappoint. Stanford professor David F. Larcker’s 2022 study of the largest companies run by handpicked successors found that most underperformed the S&P 500. This included GE after Jeff Immelt took over and Microsoft after Steve Ballmer followed Bill Gates. (Tim Cook at Apple is a rare exception.)

Between my initial interview with Larry and the announcement of his hire, in May 2007, just a few months passed. In retrospect, that wasn’t enough time to make a fully considered decision. If possible, board governance experts suggest that companies start to plan for a leadership succession three years or more in advance of an expected departure.

In 2004, Green Mountain employees had created the Purpose and Principles statement to guide our work and personal development, but at the board level, we hadn’t had much discussion about the “pillars of success” that we wanted to continue to rely on going forward. And I never specifically discussed these pillars with Larry.

I never really took Larry under my wing and introduced him to “my” version of the company culture, nor did I feel he wanted me to. After all, Larry had already managed larger companies, and because of that, I think he believed he knew everything he needed to know to run Green Mountain without input from me or the board.

As I saw Larry in action, my feeling was that he didn’t value the collaborative way of working that had gotten Green Mountain to where we were. I’d always advocated guiding and educating people but still letting them figure out the best ways to do their jobs. I did my best to let Larry do that as CEO, but it was scary for me when it felt like he was going off the playing board. Still, I was not all that sure of myself at the time and thought that perhaps I was wrong about what the company needed. So especially when the changes Larry made were small, I kept my opinions to myself.

Like many company founders, I chose to stay in my role as board chairman after I stepped down as CEO. This is a common transition: According to research by PwC, in 2019 nearly 48% of long-serving CEOs who left jobs at the world’s largest 2,500 companies either remained as board chair or assumed that role at the time of succession. But when a former “iconic” CEO stays on in a chairman role, the successor tends to struggle. Researchers from Peking and Rice Universities found that when an outgoing CEO remains as board chair, it makes the “early dismissal” of the new CEO 2.42 times more likely.

I tried to stay in my lane. It wasn’t my job anymore to make the strategic and other operating decisions that Larry was making, and I spent a lot less in-person time at the company. As chairman, I attended board meetings—but not our companywide quarterly meetings. I did not have access to many of the people in the organization. My distance was disorienting for longtime employees, who weren’t always sure what kinds of information or concerns they should share with me.

So I didn’t notice at first all the ways that Green Mountain was changing under Larry’s leadership. But soon enough, it felt to me like we were butting heads over important strategic decisions, decisions that reflected a different understanding of what our company stood for and a departure from what had made us successful so far.

In November 2012, Larry was replaced as CEO by Brian Kelley, a former Coca-Cola executive, who, to my mind, effectively dismantled what remained of Green Mountain’s culture. In 2014, the company was renamed Keurig Green Mountain, and over the next year, its stock dropped almost 70%. In December 2015, it was sold to an investor group led by JAB Holding, which also owned our former rivals Peet’s, Stumptown, and Caribou Coffee. Now, we really were just another coffee company.

Excerpt from Better and Better: Creating a Culture of Purpose, Excellence, and Transformative Human Engagement by Robert Stiller (McGraw Hill, August 2024).

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Is caffeine damaging to heart health?

23-Aug-2024 - Last updated on 23-Aug-2024 at 08:55 GMT

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Is caffeine damaging to heart health? GettyImages/Cristina_Annibali_Krinaphoto

A cup of tea or coffee is the starting point of many a morning. In fact, for most, it’s the very foundation of their day, sought out before breakfast, enjoyed during a morning break, relied upon as an afternoon pick-me-up, and then even indulged in as a post-dinner treat with dessert.

But while consumers are embracing caffeine in all its forms, including through some soft drinks and energy bars, scientists are looking at it for a very different reason: its effects on heart health.

Is caffeine damaging to heart health?

New research, presented at American College of Cardiology’s ACC Asia 2024 suggests that consuming over 400 milligrams of caffeine each day could increase the risk of cardiovascular disease.

The study, which analysed the effects of caffeine on young, ‘healthy’ adults, found that regular intake at this level disrupts the autonomic nervous system. And this disruption leads to increased heart rate and blood pressure. The research team concluded that these findings highlight the importance of moderating caffeine consumption to reduce the risk of hypertension and related cardiovascular conditions.

“Regular caffeine consumption could disturb the parasympathetic system, leading to elevated blood pressure and heart rates,” says Nency Kagathara, lead author on the study. “Due to its effect on the autonomic nervous system, regular caffeine consumption could put otherwise healthy individuals at risk of hypertension and other cardiovascular events.”

Despite this research, the European Food Safety Authority (EFSA) says that caffeine intake of up-to 400 milligrams per day does not raise safety concerns for healthy adults in the general population, with the exception of pregnant women. Though, this advice may come under review, at a later date.

However, while advice on caffeine intake levels may at some point change, it’s highly unlikely that EFSA will recommend against the consumption of caffeine altogether. And not just because it’s so widely enjoyed, but because it also offers the consumer some health benefits.

How to tell how much caffeine is in a product?

Packaged foods will often provide clear information on how much caffeine, if any, is contained within the product. Some products do not, but there are resources, such as the online database Caffeine Informer, which provide estimates for the caffeine content of certain products, including tea and coffee, so these could be used as a guide.

Caffeine group - GettyImages-mihailomilovanovic

What are the benefits of consuming caffeine?

Caffeine is a natural substance, found in the leaves and fruit of more than 60 plants, most notably, tea and coffee plants. Despite the clear association to tea and coffee, caffeine is actually present in a variety of beverages, including some soft drinks, as well as some foods, including energy bars.

As a natural ingredient, caffeine offers a variety of health benefits, with studies from Johns Hopkins Medicine in the United States associating it with a reduced risk of Alzheimer's disease, diabetes and kidney disease.

Caffeine also offers potential mental and emotional benefits when enjoyed in the form of a cup of tea or coffee.

"Coffee provides a great ritual, and really brings people together in their daily routines," Howey Gill, head of coffee at coffee brand Grind, told FoodNavigator. "Sitting down in a buzzing café, chatting, with the noise of espresso machines, customers and music - people love this vibe. At home, it provides this amazing ritual for us. Regardless of what's going on in our lives it provides this little moment of constancy where we take a second to do whatever it is we do to make our cup of coffee. For me that's pouring a big v60 for me and my partner in the exact same spot in the kitchen."

Furthermore, many consume caffeine, as it’s a natural stimulant, meaning it increases activity in the brain and nervous system. It also increases the circulation of chemicals such as cortisol and adrenaline in the body, helping the consumer to stay alert and active.

Energy bars and drinks - GettyImages-Obradovic

What does this mean for the beverage industry?

While this new research may be concerning for consumers who consume high levels of caffeine, it’s unlikely to affect consumer behaviour, unless EFSA change their advice.

It does however offer an opportunity to food and beverage manufacturers, to create caffeine-free or reduced caffeine products. And we’re not just thinking about coffee. Many sports drinks and energy bars contain caffeine, so offering an alternative for consumers looking to reduce their caffeine intake could open up a whole new market, drawing new consumers in.

Does decaffeinated mean no caffeine?

Despite the very fair assumption that ‘decaffeinated’ means no caffeine, products, such as teas and coffees labelled ‘decaffeinated’ have less caffeine than regular products, but not none.

Decaffeinated coffee, in particular, typically contains between 2 and 15 milligrams of caffeine in an eight-ounce cup. This is in comparison to around 80–100 milligrams of caffeine in an average eight–ounce cup of caffeinated coffee.

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7-Eleven Rocks Out With Exclusive Coffee Blend Collaboration

IRVING, Texas — 7-Eleven Inc. teamed up with pop punk trio Green Day to debut an exclusive anniversary blend of Green Day's coffee brand, Punk Bunny Coffee.

Starting Aug. 28, customers can find the limited-time offering at 7-Eleven, Speedway and Stripes convenience stores nationwide as part of both the the 60th anniversary of 7-Eleven originating the idea of freshly brewed coffee in to-go cups and the 30th anniversary of Green Day's breakout album.

[Read more: Possible Couche-Tard & 7-Eleven Tie Up: What Would It Mean for the Industry? ]

To celebrate the launch, 7-Eleven and Punk Bunny will give fans a chance to win free coffee. On Aug. 28, starting at 8 a.m. ET, the first 50 fans to show up at 7-Eleven at 800 6th Ave. in New York City and get inked with a custom 7-Eleven x Punk Bunny tattoo will receive free 7-Eleven coffee for 711 days. The unique, semi-permanent tattoo is designed by Lady Cobra, a fellow Bay Area native and tattoo artist who will be on-site at the event inking some fans herself.

"This year, we celebrate the 60th anniversary of 7-Eleven as the first national retailer to offer freshly brewed coffee in to-go cups, making us the OG to-go coffee destination," said Dennis Phelps, senior vice president, merchandising (vault & proprietary beverages) at 7-Eleven. "What better way to celebrate than by teaming up with Punk Bunny to bring new and exclusive coffee options to our customers and offering a one-of-a-kind coffee experience?"

The Punk Bunny Coffee Anniversary Blend was created with a multilayered experience in mind, featuring hints of citrus along with undertones of rich stone fruit before finishing with warm cocoa and a gentle hint of spice. In addition to the exclusive Anniversary Blend roast, Punk Bunny will be bringing fair trade certified coffee to 7-Eleven with bagged blends and K-Cups of the Sound Check and Last Ride In roasts available in stores.

In-store, fans will also be able to score a limited-edition Punk Bunny-inspired collectible refill mug while supplies last, while the 7Collection online shop has created a capsule of limited-time merchandise to celebrate the collaboration, including co-branded tees, totes and stickers.

Irving-based 7-Eleven Inc. operates, franchises and/or licenses more than 13,000 stores in the United States and Canada. In addition to 7-Eleven stores, the retailer operates and franchises Speedway, Stripes, Laredo Taco Co., and Raise the Roost Chicken and Biscuits locations.

7-Eleven is No. 1 on the 2024 Convenience Store News Top 100 ranking.

The Use of Green Coffee Extract as a Weight Loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials

Igho onakpoya.

Complementary Medicine, Peninsula Medical School, University of Exeter, 25 Victoria Park Road, Exeter EX2 4NT, UK

Rohini Terry

Edzard ernst.

The purpose of this paper is to assess the efficacy of green coffee extract (GCE) as a weight loss supplement, using data from human clinical trials. Electronic and nonelectronic searches were conducted to identify relevant articles, with no restrictions in time or language. Two independent reviewers extracted the data and assessed the methodological quality of included studies. Five eligible trials were identified, and three of these were included. All studies were associated with a high risk of bias. The meta-analytic result reveals a significant difference in body weight in GCE compared with placebo (mean difference: −2.47 kg; 95%CI: −4.23, −0.72). The magnitude of the effect is moderate, and there is significant heterogeneity amongst the studies. It is concluded that the results from these trials are promising, but the studies are all of poor methodological quality. More rigorous trials are needed to assess the usefulness of GCE as a weight loss tool.

1. Introduction

Overweight and obesity have become a serious health concern [ 1 ]. Different weight management strategies are presently utilised, and a variety of weight loss supplements sold as “slimming aids” are readily available. However, the efficacy of some of these food supplements remains uncertain. One such supplement is the green coffee extract (GCE).

GCE is present in green or raw coffee [ 2 ]. It is also present in roasted coffee, but much of the GCE is destroyed during the roasting process. Some GCE constituents, such as chlorogenic acid (CGA) can also be found in a variety of fruits and vegetables [ 3 ]. The daily intake of CGA in persons drinking coffee varies from 0.5 to 1 g [ 4 ]. The traditional method of extraction of GCE from green coffee bean, Coffea canephora robusta , involves the use of alcohol as a solvent [ 5 ]. Extracted GCE is marketed as a weight loss supplement under a variety of brand names as a weight loss supplement such as “Coffee Slender”, and “Svetol”.

Evidence is accumulating from animal studies regarding the use of GCE as a weight loss supplement [ 6 , 7 ]. In human subjects, coffee intake has been reported to be inversely associated with weight gain [ 8 ]. Consumption of coffee has also been shown to produce changes in several glycaemic markers in older adults [ 9 ]. Similarly, other research has indicated that the consumption of caffeinated coffee can lead to some reductions in long-term weight gain, an effect which is likely to be due to the known thermogenic effects of caffeine intake as well as effects of GCE and other pharmacologically active substances present in coffee [ 10 ]. GCE has also been postulated to modify hormone secretion and glucose tolerance in humans [ 11 ]. This effect is accomplished by facilitating the absorption of glucose from the distal, rather than the proximal part of the gastrointestinal tract.

The objective of this paper is to analyse the results of human clinical trials assessing the efficacy of GCE as a weight-reducing agent.

Electronic searches of the literature were conducted for the following databases: MEDLINE, EMBASE, CINAHL, AMED, and The Cochrane Library . Each database was searched from inception up until April, 2010. Search terms used included coffee, green coffee, green coffee extract, roasted coffee, decaffeinated coffee, chlorogenic acid, caffeoylquinic acid, antiobesity agent, appetite suppressant, abdominal fat, BMI, body mass index, body fat, body weight, overweight, over weight, corpulen*, obes*, weight loss, weight decrease, weight watch, weight cycle, weight control, weight gain, weight maintenance, weight reduction, weight change, dietary supplement, food supplement, nutraceutical, nutri*supplement, over-the-counter OR OTC, nonprescription drugs, randomised controlled trial, clinical trial, and placebo. We also searched other internet databases for relevant conference proceedings, as well as our own files. Hand searches of the bibliography of retrieved full texts were also conducted.

Only randomised, double-blind, and placebo-controlled studies were included in this paper. To be considered for inclusion, studies had to test the efficacy of GCE for weight reduction in obese or overweight humans. Included studies also had to report body weight and/or body mass index (BMI) as an outcome. No age, time, or language restrictions were imposed for inclusion of studies. Studies which involved the use of GCE as part of a combination treatment or not involving obese or overweight subjects were excluded from this paper.

Two independent reviewers assessed the eligibility of studies to be included in the paper. Data were extracted systematically by two independent reviewers according to the patient characteristics, interventions, and results. The methodological quality of all included studies was assessed by the use of a quality assessment checklist adapted from the consolidated standard of reporting trials (CONSORT) guidelines [ 12 , 13 ]. Disagreements were resolved through discussion with the third author.

Data are presented as means with standard deviations. Mean changes in body weight were used as common endpoints to assess the differences between GCE and placebo groups. Using the standard meta-analysis software [ 14 ], we calculated mean differences (MD) and 95% confidence intervals (CI). The I 2 statistic was used to assess for statistical heterogeneity amongst studies.

Our searches produced 2160 “hits”. 328 articles were excluded because they were duplicate citations, while 767 articles were excluded because of wrong titles and abstracts. Another 598 articles were excluded because they did not investigate a food supplements, and 454 articles excluded due to no report on clinical outcome. A further 13 articles were excluded due to unsuitable study design. Thus, 5 potentially relevant articles were identified ( Figure 1 ). One trial was excluded because it involved only normal weight individuals, and did not measure weight as an outcome [ 15 ]. Another trial was excluded because it was not randomised [ 16 ]. In effect, 3 randomised clinical trials (RCTs) including a total of 142 participants met our inclusion criteria, and were included in this systematic paper [ 5 , 17 , 18 ]. Their key details are summarized in Tables Tables1 and 1 and and2 2 .

An external file that holds a picture, illustration, etc.
Object name is GRP2011-382852.001.jpg

Flow chart for inclusion of randomised clinical trials.

Methodological characteristics of included studies.

Author Year Country	Main outcome (s)	Main diagnoses of study participants	Study design	Gender M/F	Attrition bias	ITT analysis
*Ayton Research 2009 United Kingdom	Body weight, waist, bust and hip circumference	Healthy overweight subjects	Parallel	Unclear

Thom 2007 Norway	Body weight, body mass index	Slight to moderately overweight subjects	Parallel	12/18	−	−

Dellalibera 1998 France	Body weight, body mass index	Overweight volunteers	Parallel	Unclear	−	−

Abbreviation: ITT (intention-to-treat); M/F: Males/Females.

Symbols: *: Unpublished study, + : Yes, −: No, ? : Unclear.

Main results of included RCTs 1 .

Author Year	GCE specification	No. of participants randomised	Age in yrs; Sex: M/F	Body weight at baseline	Dosage of GCE	Treatment duration	Main results; reported as means with standard deviations	Adverse events	Control for lifestyle factors
Ayton Res. 2009 (unpublished)	CGA enriched green coffee	62	Not reported	76.65 ± 7.25 kg (GCE) 77.44 ± 12.93 kg (PLA)	180 mg daily	4 weeks	Weight loss was 1.35 ± 0.81 kg and 0.12 ± 0.27 kg for GCE and PLA respectively	Not reported	Normal lifestyle

Thom 2007	CGA enriched green coffee	30	Not reported 12/18	85.2 ± 4.5 kg (GCE) 84.3 ± 4.3 kg (PLA)	200 mg daily	12 weeks	Mean weight loss was 5.4 ± 0.6 kg (GCE) and 1.7 ± 0.9 kg (PLA). Mean fat loss was 3.6 ± 0.3% (GCE) and 0.7 ± 0.4% (PLA)	No adverse events	Regular diet, normal level of exercise

Dellalibera 2007	Green coffee extract	50	Range: 19–75	Not reported	200 mg daily	12 weeks	Mean weight loss was 4.97 ± 0.32 kg and 2.45 ± 0.37 kg for GCE and PLA, respectively	Not reported	Not reported

Abbreviation: PLA: placebo

1 Unless otherwise specified, values are reported as means with standard deviations.

2 Values reported as means with standard errors.

A forest plot (random-effect model) for the three trials is shown in figure 2. The meta-analysis reveals a statistically significant difference in body weight between GCE and placebo (MD: −2.47 kg; 95% CI: −4.23, −0.72). The I 2 statistic of 97% suggests that there is considerable heterogeneity amongst the studies. A further plot of two trials which involved CGA-enriched GCE revealed a statistically nonsignificant difference in body weight between GCE and placebo (MD: −1.92 kg; 95% CI: −5.40, 1.56). Heterogeneity was also considerable in this analysis ( I 2 statistic of 99%). One of the studies reported a statistically significant decrease in the percentage of body fat in the GCE group compared with baseline, but no significant difference in the placebo group [ 5 ]. There was no mention of intergroup differences regarding the percentage of body fat. None of the trials reported any adverse events associated with the use of GCE.

4. Discussion

The main purpose of this systematic paper was to assess the efficacy of GCE as a weight loss supplement. The overall meta-analysis revealed a significant difference in change in body weight between GCE and placebo. The magnitude of this significance is moderate, and the clinical relevance is therefore not certain. There is also considerable heterogeneity amongst the three trials.

In animals, GCE has been reported to influence postprandrial glucose concentration and blood lipid concentration [ 5 ]. This is thought to be via reduction in the absorption of glucose in the intestine; a mechanism achieved by promoting dispersal of the Na + electrochemical gradient. This dispersal leads to an influx of glucose into the enterocytes [ 19 ]. GCE is also thought to inhibit the enzymatic activity of hepatic glucose-6-phosphatase, which is involved in the homeostasis of glucose [ 20 ]. Reports from animal studies have suggested that GCE mediates its antiobesity effect possibly by suppressing the accumulation of hepatic triglycerides [ 6 ]. Some authors have also posited that the antiobesity effect of GCE may be mediated via alteration of plasma adipokine level and body fat distribution and downregulating fatty acid and cholesterol biosynthesis, whereas upregulating fatty acid oxidation and peroxisome proliferator-activated receptor alpha (PPAR α ) expression in the liver [ 7 ].

Diets rich in polyphenols may help to prevent various kinds of diseases associated with oxidative stress, including coronary heart disease and some forms of cancer [ 21 , 22 ]. GCE has been reported to have antioxidant activity, demonstrated by its ability to scavenge free radicals in vitro , and to increase the antioxidant capacity of plasma in vivo [ 16 , 23 ]. There is also evidence that certain dietary phenols, including GCE, may modify intestinal glucose uptake in a number of ways [ 8 , 24 ]. This activity might provide a basis for explaining its effects on body weight. The purported slimming effect of GCE would have a protective effect against diabetes mellitus, via changes in gastrointestinal hormone secretion [ 10 ]. A few questions, however, arise from the RCTs which involve the use of GCE as a weight loss aid.

All the RCTs involving the use of GCE which have been conducted so far have very small sample sizes, with the largest number of participants being 62 in one trial [ 17 ]. These small sample sizes increase the possibility of spurious or false positive results. Two of the RCTs were unclear about drop-outs of participants from the trial; neither did they report on intention-to-treat analysis [ 17 , 18 ]. All of the trials so far identified have been of very short duration. This makes it difficult to assess the efficacy and safety of GCE as a weight reduction agent on the medium to long-term. Although none of the RCTs identified reported any adverse events, this does not indicate that GCE intake is “risk-free”. Two participants in a study report dropped out due to adverse events associated with the intake of GCE [ 16 ]. These included headache and urinary tract infection. Thus, the safety of this weight loss aid is not established.

The effective dosage of GCE for use as a weight loss supplement is also not established. The dosages of GCE reported in most of the human trials identified were estimated, as the GCE was a component of coffee. While 2 of the RCTs identified enriched their GCE with CGA [ 5 , 17 ], the third trial did not report that the GCE used was fortified with CGA [ 18 ]. This warrants further investigation.

The RCTs identified from our searches were not also clear on blinding issues. None of the RCTs reported on how randomisation was carried out, and none provided information regarding blinding of outcome assessors. This casts doubt on the internal validity of these trials. Future trials involving the use of GCE as a weight loss supplement should be conducted in line with the CONSORT guidelines. This will ensure the validity and applicability of study results. Two authors in one study were affiliated to a company which markets Svetol [ 18 ] but did not specify whether or not they had any conflicts of interest.

This systematic review has several limitations. Though our search strategy involved both electronic and nonelectronic studies, we may not have identified all the available trials involving the use of GCE as a weight loss supplement. Furthermore, the methodological quality of the studies identified from our searches is poor, and all are of short duration. These factors prevent us from drawing firm conclusions about the effects of GCE on body weight.

5. Conclusion

The evidence from RCTs seems to indicate that the intake of GCE can promote weight loss. However, several caveats exist. The size of the effect is small, and the clinical relevance of this effect is uncertain. More rigorous trials with longer duration are needed to assess the efficacy and safety of GCE as a weight loss supplement.

An external file that holds a picture, illustration, etc.
Object name is GRP2011-382852.002.jpg

Forest plot showing the effect of GCE on body weight.

Conflict of Interests

I. Onakpoya is funded by a grant from GlaxoSmithKline. The funder had no role in the preparation of the paper. R. Terry and E. Ernst declare no potential conflict of interests.

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Published: 20 August 2024

Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time

Jiexin Liang 1 ,
Mackenzie E. Batali 1 ,
Catherine Routt 1 ,
William D. Ristenpart 2 &
Jean-Xavier Guinard 1

Scientific Reports volume 14 , Article number: 19298 ( 2024 ) Cite this article

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Plant sciences

With the growing popularity of cold brewed coffee comes a need for brewing efficiency while preserving the desirable flavor profile. Despite the wide use of full immersion brewing techniques, the effect of brew time on the dynamic sensory profiles of full immersion brewed coffee remains underexplored. Here, we investigated the relationship between coffee sensory quality and extraction dynamics, measured as Total Dissolved Solids ( TDS ) and Extraction ( E ) of full immersion brewed coffee at various roast levels, and brewing temperatures (4 °C, 22 °C and 92 °C), over brew time using a generic descriptive analysis method. Specifically, different brew time points were selected for different temperatures based on five targeted coffee extraction stages. Furthermore, the unique experimental design also explored a sensory-driven engineering research process. Roast level had the greatest impact on the sensory profile of the coffees, followed by brewing temperature, but brew time, especially the longer brew times as TDS plateaued, had subtler impacts than expected. Twenty-five of 28 sensory attributes were significantly different among the 30 coffee samples, indicating a single source green coffee blend can produce a wide range of complex sensory profiles using different combinations of roast level, temperature, and brew time. Specifically, the intensity of sweetness was negatively correlated with TDS , and 19 other attribute intensities were positively correlated with TDS . Interestingly, we found that certain long time cold brews had similar sensory profiles to those of some short time hot brews, suggesting the sensory profiles of certain hot brews and cold brews could possibly be matched through controlled preparation. Overall, our study demonstrated an approach of integrating food engineering and sensory analysis for product development, and our findings provide valuable insights into the extraction dynamics and sensory quality of full immersion brewed coffee and opens new brewing avenues for the coffee industry.

Brew temperature, at fixed brew strength and extraction, has little impact on the sensory profile of drip brew coffee

Impact of beverage temperature on consumer preferences for black coffee

An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee

Introduction.

The importance of TDS and E on sensory quality and consumer liking of coffee has been well established 1 , 2 , 3 , 4 , 5 . While most coffee sensory studies of brewed coffee focused on pressurized espresso brew or flow-based drip brew 2 , 4 , 6 , 7 , 8 , 9 , 10 , there are comparatively less sensory studies on full immersion brewing methods other than a few recent ones focused on cold brew 10 , 11 , 12 , 13 , 14 . The connection between sensory quality and extraction dynamics of full immersion brewed coffee under various brewing conditions is also missing. Especially, for coffee cupping, the coffee industry relies on the Specialty Coffee Association (SCA) standards and protocols as guidelines to prepare coffee samples 15 . However, the effects of brewing parameters on extraction dynamics in the cupping brewing process remain underexplored. The process of cupping involves tasting the coffee at multiple time points as coffee cools down throughout the entire brewing process 15 . However, no scientific study to date has systematically assessed the dynamic sensory profile behind full immersion brewed coffee in response to various brewing parameters, such as grind size, brew ratio, brew temperature, and roast level. Moreover, the difference in extraction dynamics in response to roast level also has crucial implications for sensory quality of full immersion brewed coffee: the sensory properties of coffees with different roast levels evaluated at the same time point under the same temperature could be confounded by the difference in strength 16 , 17 . Therefore, the sensory quality of full immersion brewed coffee depends on multiple brewing parameters.

To understand the effects of roast level and key brewing parameters on the sensory quality of the brew, a combination of engineering and sensory evaluation approaches is needed to investigate how physical characteristics of the cup vary with controllable parameters, and how such measurable physical properties ( TDS and E) correlate with sensory properties of full immersion brewed coffee. For the vast majority of coffee baristas and coffee consumers, the practical question of how to brew a cup of coffee with a desired sensory profile using full immersion brewing techniques has yet to be fully answered.

Our prior sensory analysis of the effects of origin, roast level, and brewing temperature on the flavor profile of full immersion brewed coffee at fixed equilibrium TDS and cold consumption temperature showed that brew temperature across the cold to hot range has a significant impact on the sensory properties of coffee, and that different roast levels and origins also yield differences in sensory attributes with temperature 18 . Yet, this study eliminated the effect of total brew time that yields differences in final TDS , which is also a key factor in coffee cup quality 17 , 19 .

On the other hand, the coffee industry heavily relies on the full immersion method of “cupping” to evaluate coffee quality, mainly following SCA standards and protocols 15 . Despite the widespread use of this procedure and the industry’s continuous dedication to enhancing it 20 , questions remain about the consistency and effectiveness of this sensory evaluation process used in the industry 21 , 22 , 23 , and there is still a need for published scientific justification of the details of the protocol. We therefore wanted to answer the following questions: how does the sensory profile of the coffee cup change over time after water addition, as it continues to extract, and cools down to room temperature? How does this dynamic sensory profile change in response to different roast levels and brewing parameters? What are the relationships between the physicochemical measurements ( TDS , pH, and TA) and the sensory quality of coffee over time? How do we design the sensory profile of immersion coffee via actionable brewing parameters?

To answer these questions, this study related the extraction dynamics to the sensory quality of full immersion coffee following a sensory-driven engineering approach. We explored the flavor profiles and investigated the effects of roast levels, brewing temperatures, and brew time on the sensory quality of full immersion brewed coffee using a generic descriptive analysis method in conjunction with TDS , TA, and pH measurements.

Experimental design

We used a 2 × 3 × 5 factorial design, with a Central America coffee blend roasted to 2 different roast levels, and each brewed at three different temperatures (4 °C, 22 °C, and 92 °C), to five different time points that corresponded to five brewing stages from “rinse” to equilibrium of full immersion brews. Each of the 30 coffee samples were prepared in triplicate for both physical/chemical and sensory measurements. The physical/chemical properties of the coffees were measured as total dissolved solids ( TDS ), titratable acidity (TA), and pH, and the sensory properties of the coffees were evaluated using a generic descriptive analysis method.

A Central American blend coffee composed of an El Salvador Cerro Las Ranas coffee and a Nicaragua Parainema coffee was roasted to two different roast levels, representing a “light” roast, denoted by light roast (L), and a darker end of “medium-dark” roast, denoted by dark roast (D) 24 . Roasting was done in a single day using a Probat Probatone P-5 roaster (Probat-Werkevon Gimborn Maschinenfabrik GmbH, Emmerich am Rhein, Germany) at the UC Davis Coffee Center. The average roast colors of the roasted beans were 71.8 and 41.8 for the light and dark roasts, respectively, measured using an Agtron Gourmet Color Scale 25 (Agtron E2OCP-II Coffee Analyzer, Agtron Inc., Reno, NV, USA). Roasted beans were degassed for a week at room temperature, then vacuum-sealed in bags and stored in a freezer at − 20 °C following the same protocol as in previously published coffee studies 16 , 18 . To ensure consistent sensory quality, individual bags of coffee were defrosted at room temperature overnight before use.

Coffee brewing

A schematic visualization of the brewing and serving process is shown in Fig. 1 . All roasted coffee beans were ground to a consistent grind size setting of 4, corresponding to a median particle size of $972\pm 19$ μm (cf. Supplemental Fig. S1 in 19 reference) in a classic Mahlkönig Guatemala Lab Grinder (Mahlkönig USA, Durham, NC, USA). Coffees from each roast level were brewed using water at three different temperatures: 4 °C (typical temperature of refrigeration), 22 °C (room temperature), or 92 °C (within the range of suggested temperature for hot brewed coffee 26 ). The refrigerator and room brews were brewed for 0, 4, 8, 12, and 24 h and the hot brews were brewed for ‘0’, 4, 10, 30, and 60 min, each corresponding to time points denoted as T1, T2, T3, T4, and T5, respectively. Time points were chosen based on representative extraction stages of full immersion brews: T1 was the “rinsed” coffee, T2 and T3 were during and near finish of the rapid increase in TDS , and T4 and T5 were after the TDS of the brew had reached apparent equilibrium 19 .

A schematic of coffee brewing and the sensory evaluation process.

All coffees were brewed using a full immersion brewing technique in Toddy Cupping Kits (Toddy LLC., Loveland, CO, USA) with Nestlé Pure Life Purified Water 27 (Nestlé Waters North America Inc., Stamford, CT, USA) at a water-to-coffee brew ratio ${R}_{brew}=5$ , which is a typical brew ratio the industry uses for cold brew concentrate 28 . For the refrigerator temperature brews, water was pre-refrigerated to 4 °C; for the room temperature brews, water temperature was set at 22 °C; for the hot brews, water was heated to 92 °C using a Bonavita 1.7-L Variable Temperature Electric Kettle (Bonavita World, Woodinville, WA, USA). All coffees were brewed using the following full immersion technique: First, 100 g of coffee grounds were measured and placed into the glass container, and 500 g of water at target temperatures (4, 22, or 92 °C) was poured into the beaker using a goose-neck kettle in circular pouring motion. The timing of the brew started upon completion of the water pouring (time = 0). Then, with the only exception of the “rinsed” coffee which was immediately filtered, the coffee brews were stirred with a stirring stick for 15 s to ensure all coffee grounds were fully wet. After that, the brews were covered with a lid, and brewed to the designated brew time. During brewing, the fridge brews were stored in a refrigerator at 4 °C, while the room and hot brews were placed on a wooden countertop at room temperature. When the brew reached the designated brew time, a filtration step was applied, in which the entire coffee brew was filtered through a filter paper to separate the liquid coffee brew from the coffee grounds. Two identical brews were carried out per brewing condition. The resulting coffee liquid brews from the identical brews were combined into a coffee concentrate, in which a 2 mL sample was drawn using a disposable pipet for TDS measurements. Then, the coffee concentrate was diluted with room temperature water by a factor of 2 by mass to obtain the diluted coffee beverage. A 100 mL sample was collected from the coffee beverage for physical/chemical measurements, and the rest of the diluted coffee beverage was stored at 4 °C overnight before sensory evaluation the next day. All coffee types were brewed in triplicate.

Physical and chemical measurements

The total dissolved solids ( TDS ) were measured for both the coffee concentrate before dilution and the coffee beverage after dilution at room temperature using a VST LAB Coffee III digital refractometer (VST Inc, Boston, MA, USA). The refractometer was calibrated according to procedures outlined in a prior study 19 . The corresponding extraction yield, E , was calculated form the measured TDS and ${R}_{brew}$ using the following equation 19 :

The pH and titratable acidity of the coffee beverage after dilution were also measured at room temperature using a Mettler Toledo S220 SevenCompact™ Benchtop pH/IS E Meter (Mettler Toledo, Greifensee, Switzerland). The pH measurements were taken while the sample was stirred using a magnetic stir bar. Then, while the coffee was stirred, the titratable acidity was measured by adding 0.1 M NaOH (Sigma Aldrich, St. Louis, MO, USA) dropwise from a burette, until the solution reached a pH of 8.20 ± 0.01. Titratable acidity is expressed in mL NaOH/50 mL coffee. The pH meter was calibrated using acidic (pH 4.00 ± 0.01, color coded red), neutral (pH 7.00 ± 0.01, color coded yellow), and basic (pH 10.00 ± 0.01, color coded blue) calibration standards (VWR chemicals, VWR international, Radnor, PA, USA) before every set of six measurements. Physical/chemical measurements were conducted in triplicate, consistent with the samples tasted in descriptive analysis.

Descriptive analysis

The training and sensory evaluation protocols were adapted from a generic descriptive analysis in accordance with approved amended IRB protocol 1082569-2. The panel was composed of 14 panelists, including 10 women and 4 men. In the Fall of 2021, ballot development and training were conducted in a group setting over nine 1-h training sessions, where panelists tasted the coffees and engaged in free term generation, drawing inspiration from the Coffee Taster's Flavor Wheel 29 . Following the selection of 27 attributes, panelists engaged in additional discussions and training to come to consensus and familiarize themselves with reference standards for all attributes incorporated in the final ballot. During the last week of training, panelists received reference materials alongside coffee samples, allowing them to work directly with the references while tasting coffees. All the attributes on the ballot are listed along with reference standards in Supplementary Table S1 . Before the actual evaluations, panelists conducted two mock sessions with a subset of the coffees to ensure alignment among panelists.

For the actual sensory evaluation, panelists participated in 15 tasting sessions, assessing 6 coffees per session. The evaluations were conducted in temperature-controlled, red-lit sensory booths to ensure panelists were isolated and not influenced by visual differences among the coffees. Samples were assigned a 3-digit random code and presented in a randomized Williams Latin Square block design to mitigate carryover effects. Coffees were presented to panelists one at a time, with a 2-min interval between samples. Data collection was conducted on RedJade (RedJade, Redwood City, CA, USA), where participants rated each attribute on an unstructured line scale ranging from 0 to 100, with anchor points at 10 and 90 labeled only with the words “Low” and “High”. Each coffee was evaluated in triplicate by the panelists on separate days. Coffee samples (50 mL) were served in white ceramic mugs. To maintain a consistent consumption temperature for all panelists, coffee samples were served cold around 6 °C and gradually warmed to around 12 °C within 3 min during the tasting. Unsalted saltine crackers, water, and an empty cup for expectoration were provided to all panelists.

Data analyses

Descriptive analysis data were exported from the data collection software, and ratings on the unstructured line scales were converted to scores from 0 to 100 for each attribute. All statistical analyses were conducted using RStudio 2022.07.1 Build 554. To understand the sensory characteristics of the coffee samples, Multivariate Analysis of Variance (MANOVA) across all attributes, and Analysis of Variance (ANOVA) of individual attributes were used to determine which attributes were significantly different across the set of coffees. A three-way MANOVA (Product, Judge, Replication as factors) with two-way interactions using Type III sums of squares (SS) was used to analyze all the attributes at 5% significance level of alpha. The Wilk’s Lambda test was used in MANOVA. Following a significant MANOVA result, univariate three-way ANOVAs with two-way interactions on each attribute were conducted with Type III sums of squares at the same significant level. For any attribute, if the main product effect was significant, and a Product*Judge or Product*Replication effect was significant in the univariate ANOVA, a pseudo-mixed ANOVA using the mean square of the corresponding interaction effect as the error term was used to test the main product effect. Then, a five-way MANOVA (Roast, Origin, Temperature, Judge, Replication as factors) with up to three-way interactions using Type III sums of squares (SS) was used to analyze all the significant attributes at the same significance level. Attribute means determined to be significant for the experimental factors, including the ones from judge or replication effect by pseudo-mixed ANOVA, were then compared using Fisher’s Least Significant Difference (LSD) in the “agricolae” package.

Principal Component Analysis (PCA) based on the significant attribute means was used to visualize the sensory profiles of the 30 coffee samples. A correlation PCA was conducted using the “SensomineR” package, and a PCA biplot was created using the “factoextra” package. The first three dimensions were investigated and interpretations were focused on the first two dimensions. In addition, a correlation PCA based on the raw attribute ratings was conducted using Bootstrap techniques to display 95% confidence ellipses around products using the “SensoMineR” package. Pairwise comparisons of the products using Hotelling’s T2 tests were also generated by the same function.

Correlation analysis between the intensity of sensory attributes and physical/chemical measurements was conducted, and the corresponding correlation plot was generated using the “corrplot” package. Furthermore, Multiple Factor Analysis (MFA) was conducted based on means of significant attribute intensities using Time Point as groups to visualize the sensory profiles over time. The MFA compromise space was generated using the “FactoMineR” package, and the score plot and loading plot were generated using the “factoextra” package.

Physical and chemical measures

Overall, the TDS before and after dilution, extraction, and titratable acidity increased as brew time increased as shown in Fig. 2 . All coffees were brewed to set times, which corresponded to target timepoints dependent on temperature. The 92 °C brews reached higher equilibrium TDS before dilution than the 22 °C and 4 °C brews, with averages of ( $3.97\pm 0.63)\%$ , ( $3.93\pm 0.10)\%$ , and ( $3.52\pm 0.59)\%$ at the final timepoint, respectively. Consistent with previous studies 18 , roast level also affected the extraction dynamics, with the light roast being extracted faster and reaching higher TDS values than the dark roast at every time point, with this effect being the most pronounced for the 4 °C brews. Coffee brews were diluted by a factor of two for sensory evaluations and chemical measurements. Thus, the TDS after dilution and calculated extraction yield based on the concentrated TDS followed the same trends as the TDS before dilution.

Scatter plot of the means and standard deviations of ( A ) TDS before dilution, ( B ) TDS after dilution, ( C ) Extraction before dilution, ( D ) Titratable Acidity, and ( E ) pH over time; roast levels are represented with different colors.

The titratable acidity of the coffee samples varied significantly for roast, temperature, and brew time, while the pH only varied significantly with roast and temperature (cf. Fig. 2 D,E). The light roast coffee had significantly higher titratable acidity and lower pH. Since titratable acidity is correlated with perceived sourness 7 , our results indicated that the light roast was more sour/acidic than the dark roast regardless of brewing temperature or brew time. The effect of temperature was smaller compared to that of roast; overall, the titratable acidity increased, and pH slightly decreased with brewing temperature. Furthermore, the titratable acidity of the coffee increased with brew time, but pH remained stable as brewing proceeded.

Sensory measures

The three-way MANOVA with two-way interactions across all attributes showed that the main product (coffee samples) effect was significant. In addition, Judge, Rep, and two-way interactions also were significant (p-value < 0.05). Following the significant MANOVA, univariate three-way ANOVAs with two-way interactions for each attribute found that 25 out of the 28 attributes in the scorecard (all attributes except black tea, paper, and herbal) differed significantly among the 30 coffee samples (cf. Supplementary Table S2 ), indicating a wide range of sensory profiles within this product set. For comparison, the line plots of perceived attribute intensities of all attributes for both roast levels and brewed at three different temperatures over the different time points are shown in Fig. 3 . Within this product set, some attributes' intensities varied largely with the experimental factors tested, such as, astringent, bitter, burnt, citrus, cocoa, roasted, rubber, smoky, and sour; while some attributes' intensities remained within a smaller range with respect to the change of experimental factors, such as broth, brown spice, brown sugar, cooked green, earthy, floral, savory, and whiskey.

Line plots of mean attribute Intensities over time points of light and dark roasts. Time points 1, 2, 3, 4, 5 correspond to 0, 4, 8, 12, 24 h for 4 °C and 22 °C brews, and 0, 4, 10, 30, 60 min for 92 °C brews. Dark roast samples are represented with solid lines, and light roast samples are represented with dashed lines. Different brewing temperatures are represented with different colors, error bars represent the LSD values for each attribute from the 3-way ANOVA with interactions.

Furthermore, the five-way MANOVA examining the effects of experimental factors showed that roast level was the largest driver of differences among the samples, followed by brewing temperature, then brew time, especially the longer brew times as TDS plateaued. Fourteen attributes were found to be significant for all three experimental factors—roast, temperature, and time (i.e., bitter, sour, cocoa, berry, citrus, rubber, nutty, roasted, fermented, burnt, smoky, earthy, and brown spices) (cf. Table 1 ). Additionally, fruity, cooked green, and fresh green were significantly different between roasts; sweet, savory, viscous, astringent, and whiskey were significantly different both among temperatures and across times; and brown sugar differed significantly among temperatures. Notably, many of the significant attributes by roast, temperature, or time showed significant two-way interaction(s) among the three experimental factors.

Relation between sensory and physical/chemical measures

Because the TDS and E are highly dependent on brew time, the relationship between the attribute intensities and TDS was investigated. Correlation analyses revealed that 19 attributes were positively correlated to TDS and E, while sweetness was the only attribute negatively correlated with TDS and E, and the remaining 8 attributes showed no statistically significant relationship with TDS or E (cf. Fig. 4 ). These findings suggest that most attribute intensities increased with TDS as brewing proceeded. Furthermore, correlation analyses between attribute intensities and chemical measurements were also conducted. Sour, berry, fruity, citrus, and fermented had the strongest positive correlations with titratable acidity, and negative correlation with pH, indicating those attributes were highly related to the acid content of the coffees.

Correlations between physical/chemical measurements and attribute intensities. The absolute values of the correlation coefficients are reflected by the size of the circles. Significant positive correlations are indicated by blue circles, significant negative correlations are indicated by red circles, and the non-significant correlations are left blank.

Effects of roast, temperature, and time

The 5-way ANOVA results show that the 17 attributes were significantly different by roast, as the largest driver of difference among the 30 coffee samples (Table 1 ). Roast level had the biggest effect on the following attributes in order of magnitude—burnt, sour, bitter, citrus, cocoa, smoky, roasted, rubber, and fruity, as indicated by decreasing F-values (Table 1 ). Overall, dark roast coffee brews had significantly higher bitter, burnt, smoky, roasted, rubber and cocoa intensities, while the light roast coffee brews were significantly more sour, citrusy, berry-like, and fruity (cf. Fig. 3 ), which is consistent with prior works 18 , 30 . Notably, fruity was only significant for roast, suggesting that the fruity flavor of the coffee was predominantly determined by roast level with light roast being significantly fruitier regardless of the brewing process.

Temperature was the second largest driver of difference of the three experimental factors, with 20 attributes significantly different by temperature from the 5-way ANOVA. Similarly, bitter, burnt, smoky, rubber, sour; additionally, astringent, sweet, whiskey, citrus and earthy were also important attributes that varied by temperature (cf. Table 1 ). Sweetness significantly increased with decreasing temperature in dark roast, and the sweetness in the 92 °C light roast was significantly lower than in the 4 or 22 °C brews (cf. Fig. 5 A). In contrast, sour and citrus were significantly higher in the 92 °C brews for both roast levels, due to the low perceived flavor intensities in the “rinsed” coffee at 22° and 4 °C (cf. Fig. 5 I,J). Furthermore, many of the differences by temperature also depended on the roast. For dark roast, bitter, burnt, smoky, rubber, astringent, whiskey, and earthy notes significantly increased with brewing temperature from 4 °C, 22 °C, to 92 °C, while the changes with respect to temperature in light roast were not significant between the 4 °C and 22 °C brews (cf. Fig. 5 B–H). These attribute intensities were significantly lower than 92 °C brews, except for whiskey, for the same reason that the “rinsed” coffee at 22 °C and 4 °C were lacking those flavors.

Sensory attributes with significant differences by temperature and roast level across all time points, with different letter codes indicating significant difference.

Surprisingly, the effect of time was the smallest within the experimental factors tested, and under our experimental brewing protocol, in which diluted coffee concentrates were evaluated. We therefore note that the effect of brew time could have been diminished compared to a typical coffee cupping or French-press method with a higher brew ratio. Within our experimental sample set then, Time Point 1 “rinsed” coffee was sweeter, while the other significant attributes had lower intensities. Interestingly, astringent and viscous, as mouthfeel and/or chemesthesis attributes, were only significant for temperature and time. Regardless of roast level, at 4 °C and 22 °C, both astringency and viscous mouthfeel generally increased with time (cf. Fig. 6 ). Despite the fact the “rinsed” coffee was significantly lower in intensity than all the other brews, the fridge and room brews for 8, 12, and 24 h were significantly more astringent than the 4-h brew, and the 12- and 24-h fridge brews were significantly more viscous than the 4-h brew. At 92 °C, the “rinsed” coffee was significantly lower in both viscous mouthfeel and astringency compared to the other timepoints. Furthermore, the effect of time was more pronounced at lower brewing temperature, but it also depended on roast level for specific attributes (cf. Fig. 7 ). For example, for dark roast, the changes in bitter and burnt attributes were significant over time in fridge and room brews, while the changes in hot brews remained relatively stable. Conversely, sour and citrus had more pronounced differences for light roast at lower temperature brews, such that the Light—4 °C—24 h brew had significantly higher sour and citrus notes compared to the Light—4 °C—4 h brew.

Sensory attributes with significant differences by temperature and time point across all roast levels, with different letter codes indicating significant difference.

Sensory attributes with significant differences by roast level, temperature, and time point, with different letter codes indicating significant difference.

Principal component analysis (PCA)

The correlation PCA biplot of the 25 significant attributes across 30 coffee samples is shown in Fig. 8 . The first two dimensions explained 85% of the total variance, and the third dimension explained another 6%. These results accord with the 5-way MANOVA, as the coffee samples were separated the most by roast level. More specifically, attributes typically associated with dark roasts, for example, burnt, smoky, roasted, rubber, and bitter, contributed to the first dimension; and other attributes including fermented, savory, broth, sour, were important contributors to the second dimension of the PCA (cf. Supplementary Fig. S1 ). Additionally, the 0-min “rinsed” coffees at 4 °C and 22 °C were very different from all the other brews with much higher sweet and floral intensities and lack of other flavors.

Principal component analysis biplot of coffee samples and significant sensory attributes from 3-way ANOVA. Different brewing temperatures are indicated by different colors. Nomenclature of the coffee samples are represented by: Roast (L: light roast/D: dark roast)—Temperature (4/22/92 °C)—Time Point (T1/T2/T3/T4/T5). Time points T1, T2, T3, T4, T5 corresponds to 0, 4, 8, 12, 24 h in 4 °C and 22 °C brews, and 0, 4, 10, 30, 60 min in 92 °C brews. See Supplementary Fig. 1 for important contributors to the first two PCs.

The PCA further demonstrates that the effect of brewing temperature depended on roast level. For dark roast coffee brews, there was a separation by temperature, such that the 4 °C brews were higher in sweet, and floral intensities, 92 °C brews were more bitter, burnt, smoky, and astringent, and the 22 °C brews were somewhere in between. For light roast coffee, the separation of samples among the different temperatures was less clear on the PCA biplot. Similarly, the effect of brew time also depended on brewing temperature. In addition to the 0-min “rinsed” coffee at 4 °C and 22 °C being unique compared to all the other samples, clearer separations among coffees at lower brewing temperature were seen. More specifically, the dark roast coffees brewed at 4 °C exhibited some characteristics of shorter brews, and were sweeter and less bitter, roasted, or burnt. However, 92 °C coffee brews, at a given roast level, were very similar to each other.

Interestingly, for the light roast, the 92 °C “rinsed” coffee (L-92-T1) was very close to some of the 4 °C and 22 °C brews, such as samples L-4-T3 and L-4-T4, as shown in the PCA biplot. The p-values from multivariate pairwise comparisons between the coffee samples, except the “rinsed” coffee at 4 and 22 °C, are shown in Table 2 . The Hotelling’s T2 test results revealed that, for light roast coffee, the sensory profiles of these long-time cold brews and short-time hot brews were not significantly different from each other, suggesting that the sensory profiles of these coffees were similar. However, this finding was roast dependent, and for dark roast, the short-time hot brews were significantly different from almost all of the long-time cold brews.

Multiple factor analysis (MFA)

The MFA using time points as a reflection of extraction stages as groups is shown in Fig. 9 . The first two dimensions accounted for 85.9% of the total variance, and the third dimension explained another 5.7%. Again, samples were separated primarily by roast level, then by brewing temperature, with the light roasts on the left and dark roast on the right side of the first dimension (cf. Fig. 9 A). The partial axes plot also revealed that the differences by temperature also depended on the roast level. More specifically, light roast coffees brewed at 4 °C and 22 °C were closer to each other compared to the 4 °C and 22 °C brews from the dark roast, indicating that room and fridge brews using light roast coffee were more similar to each other compared to those brewed using the dark roast (cf. Fig. 9 A). The MFA further demonstrates that light roast coffee samples across brew temperature and brew time were more similar to each other compared to the dark roast coffee samples, since they are positioned closer to each other with shorter partial axes. Thus, it is consistent with the multivariate pairwise comparison results that the sensory profiles of short hot brews and long cold brews were more similar in light roast coffee. Furthermore, the coffee samples from Time Point 1 was again the most different from the other time points, while the coffees brewed after the “rinsed” stage were much closer to each other (cf. Fig. 9 B). Moreover, the correlation circles of variables at different time points also showed that the sensory profiles of this product set did not change very much after Time Point 1 (cf. Fig. 9 C), indicating that longer brew times had a much smaller effect on the sensory profiles of full immersion brewed coffee compared to roast level and brewing temperature.

( A ) Individual factor map with partial axes correlation plot, ( B ) group representation, and ( C ) correlation circles by group from MFA using time points (T1, T2, T3, T4, T5) as groups.

The effect of brew time

Our analyses consistently found that brew time was the least substantial driver of sensory differences among the full immersion brewed coffee samples compared to roast level and temperature. Coffees from Time Point 1 were clearly different from the rest of the coffees regardless of roast or brewing temperature; yet, few statistically significant changes were observed in the sensory profiles of coffees brewed beyond Time Points 3 as TDS plateaued. Another reason why brew time had such a small effect possibly is that time points corresponding to each extraction stage as a factor were used instead of the actual continuous brew time as a parameter. While the variance within treatment is larger due to the natural difference in TDS within the same Time Point at different brewing temperatures (cf. Supplementary Fig. S2 ), it is harder to find differences comparing to the variance between treatments. Thus, there is more control over roast level and brewing temperature, but comparatively less control over the final TDS corresponding to different brew times at different brewing temperatures due to the natural difference in extraction dynamics of full immersion brews 16 , 19 .

Similarly, a previous fractionation study of the flavor profiles of drip brew coffee over time had also found strong correlations between attribute intensities and TDS , which was naturally imposed by brew time 6 . In the present study, we found that bitterness, sourness and astringency were positively correlated with TDS , whereas sweetness was negatively correlated to TDS . It is important to note that the coffee samples evaluated in full immersion brews were at their accumulative TDS from $t=0$ brewed up to a certain time point; in contrast, coffee samples evaluated in the drip brew study were at their instantaneous TDS , which corresponds to a fraction of a “whole brew”, in which each fraction was collected at 30 s increments of the brewing period. This suggests that TDS , rather than the actual brew time, acts as the factor driving flavor in both drip brew and full immersion brews. Interestingly, sweet and floral attributes were perceived with higher intensity towards the end of the drip brew, while sweetness was perceived as more intense at the beginning of full immersion brews, in both cases due to the lower TDS levels. Here, the perception of sweetness probably is more related to the impression of sweetness and the absence or low level of other flavors such as bitterness and acidity rather than actual perceived sweetness 4 , 5 , 6 . Additionally, the lack of a significant correlation between floral and TDS in this study might be due to the specific beans used, as floral aroma was not a significant attribute within the coffee sample set we tested, and coffee origin was found to be the second most influential factor in the variations among full immersion brewed coffees 4 . This observation suggests that the floral characteristics of the Central American blend used in this study might not have been pronounced, and other coffees may be impacted differently by brew time.

Short-time hot chilled brews vs. long-time cold brews

An interesting finding is that the sensory profiles of certain short-time hot brews, especially the 92 °C “rinsed” coffee, were similar to those of long-time cold brews at 4 °C and 22 °C for the light roast coffee we used, indicating an overlap in sensory perception between short-time hot brew and long-time cold brew for the full immersion brewing technique. Yet, the extent of this overlap remains unclear and appears to be dependent on the roast level of the coffee, as this overlap was much more obvious in the particular light roast coffee we used in this study. To further validate this finding, discrimination testing will be needed to compare coffee samples brewed from long-time-cold-temperature and short-time-hot-temperature from a wider range of pre-brewing conditions including origins, processing methods, storage conditions, and roast levels.

Furthermore, other coffee brewing and coffee serving parameters also contribute to this overlap. In our experimental approach, we brewed the coffee concentrate and then diluted it by a factor of 2 the day prior to sensory evaluation, then the coffee beverages were chilled in the refrigerator before serving. Noted that this approach resulted in a lower brew ratio than a standard coffee cupping preparation protocol or a typical French press brewing method; in this manner we attempted to minimize the effect of varied serving temperature on sensory perceptions, by serving all coffee samples at a controlled, cold temperature. As a consequence of this approach, however, another potential confounding factor is that the overnight storage time might affect the chemical composition and sensory profile of the coffee, if it is stored at refrigerated temperature 31 . More detailed chemical analyses would be necessary to test this hypothesis.

Practical implications

The overarching finding from our sensory analysis is that roast was the main driver of the overall flavor profile of full immersion brewed coffee, while temperature and time provided tools to optimize attribute intensities for the flavor profile of the roasted coffee beans we used. By examining the dynamic sensory profile of cold brews under different brewing parameters over time, our results not only strengthened the scientific understandings of existing common cold brew industry practices, but also provided insights for improving brew control and efficiency. For instance, fruity flavor, an important driver of consumer liking 1 , 2 , 4 , 5 , was only significant by roast level, suggesting that darker roasts may hinder the expression of fruitiness regardless of brewing temperature or brew time. Previous sensory analysis of full immersion coffee that examined the flavor profile of full immersion brews at fixed TDS found that the difference within the coffee sample was driven by roast level, origin, and then temperature 4 . Thus, when aiming to achieve specific sensory properties of coffee using full immersion brewing, it is crucial for practitioners to prioritize designing the roast of the coffee beans, followed by the temperature, and lastly, the longer brew times, especially after Time Point 3 as the TDS approaches equilibrium. When brewing light roast coffee, it is worth considering the possibility of achieving similar sensory profiles of long-time cold brews using short-time chilled hot brews through a controlled preparation method. Although similar flavor profiles can be obtained in a shorter time, the energy required for brewing water and chilling the coffee should be considered. From efficiency improvement aspects, a noteworthy implication is the potential for shorter brew times in crafting cold brew than conventionally assumed. The current general practice of cold brew falls between 12 to 24 h 12 , 28 , 32 , 33 . We observed very few statistically significant changes in the sensory profiles after Time Point 3 (8 h at 4 °C and 22 °C), suggesting that the industry can increase efficiency in full immersion styled cold brew coffee by reducing brew time without changing any other brewing conditions.

Conclusions

Our study demonstrated the significant impact of roast level, temperature, and brew time on the sensory quality of full immersion brews. A wide range of flavor profiles were achieved from a single source green coffee blend through combination of these factors, with roast level as the biggest driver of flavor, followed by temperature, then the longer brew time points as TDS plateaued. Furthermore, perceived sweetness was negatively correlated with TDS , while 19 other attributes had a significant positive correlation with TDS . Interestingly, certain short-time hot brews, especially the 92 °C “rinsed” coffee, had similar sensory profiles to those of long-time cold brews at 4 °C and 22 °C for the light roast, although this similarity may depend on roast level and characteristics of the coffee beans used. These findings provide valuable understandings of the effects of coffee preparation factors on extraction and sensory profiles of full immersion coffee over time, and bring new practical insights into the control of sensory quality of full immersion brews for the coffee industry.

Data availability

All data generated and analyzed in this study are available at Dryad Digital Repository, https://doi.org/10.5061/dryad.v15dv423h .

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Acknowledgements

We would like to thank the Coffee Science Foundation for support of this research, with underwriting from Toddy LLC. We would also like to thank Juliet Han for roasting the coffee for this research, Prof. Hildegarde Heymann for help and guidance in sensometrics, and students at the UC Davis Coffee Center and the UC Davis Department of Food Science and Technology who assisted in data collection: Megan Dunkin, Kiev M. Ung, and Keona L. Kanthatham.

This study was funded by the Specialty Coffee Association with underwriting from Toddy LLC.

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Jiexin Liang, Mackenzie E. Batali, Catherine Routt & Jean-Xavier Guinard

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J.L. co-designed the study, conducted experiments, performed data analysis and figure preparation, and wrote the original draft of the manuscript. M.E.B co-designed the study, conducted the experiments, and edited the manuscript. C.R. conducted experiments. W.D.R. and J.-X.G. secured funding, co-designed the study, advised data analysis, and edited the manuscript.

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Liang, J., Batali, M.E., Routt, C. et al. Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time. Sci Rep 14 , 19298 (2024). https://doi.org/10.1038/s41598-024-69867-6

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UC researchers continue to blaze new trails in science, medicine, business, education, engineering and the arts — literally transforming the way we live, work and learn.

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Announcing the Michelman Green, Clean, and Sustainable Technology Research Innovation Program Grantees

Courtesy of the generous contributions of the Dr. John S. Michelman Fund for the Advancement of Sustainable Technology, the Michelman Green, Clean, and Sustainable Technology Research Innovation Program supports applied R&D and use-inspired research with the potential to meaningfully contribute to improvements in environmental health, environmental stewardship, and sustainability by demonstrating new and marketable scientific and technical innovations intended to address real-world problems in the Green-tech and Clean-tech fields.

Applicants for the third cohort of Michelman grantees could apply as either single investigators or multi-investigator teams. Grantees were selected based on the quality, novelty, and creativity of their proposed applied research topic which demonstrated a clear potential to make tangible contributions that improve societal outcomes. Single investigator grantees were awarded up to $35,000 and multi-investigator teams were eligible for up to $80,000 for a 24-month project period to accelerate their applied R&D activities to the point that they can obtain external funding.

Congratulations to the following grantees!

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The project investigates novel mathematical optimization approaches for lightweighting of architectural slab structures. This allows for a reduction of materials and their associated CO2 impact in the construction of buildings, one of the main contributors to greenhouse gas emissions.

Highly selective recovery of high value-added materials from electrical and electronic wastes for energy storage

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Electrical and electronic waste (e-waste) is increasing rapidly due to the rising consumption of batteries in portable electronics, electric vehicles, and renewable energy storage systems worldwide. E-waste recycling conserves valuable raw materials such as gold, silver, copper, and rare earth elements. This reduces the need for mining, lowers environmental pollution, and mitigates risks to public health.

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Living in tree-filled neighborhoods may reduce risk of heart disease, study shows

Living in a tree-filled neighborhood may be as beneficial to the heart as regular exercise, new research shows.

Researchers at the University of Louisville designed a clinical trial that followed hundreds of people living in six low- to middle-income neighborhoods in South Louisville, Kentucky. They used blood and other samples to better understand how their heart risks changed before and after the team planted thousands of mature trees near their homes.

Results from the Green Heart Louisville Project ’s HEAL Study , released Tuesday, showed that people living in neighborhoods with twice as many trees and shrubs had lower levels of a blood marker associated with heart disease, diabetes and some types of cancer compared with those who lived in more tree-bare neighborhoods.

“We are trying to see if we can decrease the rates of heart disease in a community,” said Aruni Bhatnagar, a professor of medicine at the University of Louisville, who led the project.

Most previous studies showing the effects of nature on mental and physical health are observational and can’t answer whether people who live in green communities are healthier because they’re wealthier and have access to better health care.

The HEAL study was set up with a control group and an intervention, meaning something measurable that some of the participants were exposed to during the study but not before.

Bhatnagar and his team recruited about 750 people living in a 4-mile area of South Louisville cut by a highway. The residents were 25 to 75 years old.

Nearly 80% were white, and 60% identified as female. Half reported average household incomes of $50,000.

The researchers collected blood, urine, nail and hair samples, as well as health data, from each person before they began their intervention.

Then, from 2019 to 2022, they planted nearly 8,500 evergreen trees, 630 deciduous trees — the type that lose leaves in the fall — and 45 different types of shrubs in parts of the 4-mile study area, leaving others untouched.

Last year and this year, they took new samples from residents living in both areas.

People living in the intervention areas had 13% lower levels of high-sensitivity C-reactive protein , a blood marker associated with heart disease, including stroke, coronary artery disease and heart attack. The drop was similar to starting a regular exercise routine, Bhatnagar said.

“I wouldn’t have expected such a strong biomarker response, and that speaks to maybe something truly is causal here with how trees impact health,” said Peter James, director of the Center for Occupational and Environmental Health at the University of California, Davis School of Medicine, who wasn’t involved in the new research.

How trees can improve physical health

Previous research has shown spending time in green spaces boosts mental health .

The new study showed the connection between living among more trees and physical health.

Trees provide shade and cool the areas where they’re planted, helping quell the urban heat effect that disproportionately affects low-income neighborhoods and neighborhoods of color. Hot weather aggravates heart disease and can cause heatstroke in people without pre-existing conditions.

Trees also buffer noise, which is linked to higher rates of cardiovascular disease, James said.

“They provide areas for people to relax, exercise, and probably more importantly, socialize,” Joan Casey, an environmental epidemiologist and associate professor of environmental and occupational health sciences at the University of Washington, said in an email.

“They also replace other health-harmful land uses, like industrial sites,” she said.

Because one of the city’s major highways cuts through the study area, Bhatnagar and his team believe, trees’ ability to filter air pollution and buffer neighborhoods from constantly breathing in harmful particles could be a primary way the tree-planting intervention appeared to lower inflammation markers in people living in greened areas.

During the study, the project planted trees only in the parts of South Louisville that had the worst air quality. It took air quality samples before the project, and it is still analyzing how the new tree cover has affected pollution. It’s a complex undertaking, because air quality fluctuates based on the weather — a windy day might increase or decrease air pollution in certain areas, depending on the direction of the wind, and air pollution is worse on hotter days.

The project plans to plant trees in the control group neighborhoods in another three or four years if the intervention neighborhoods continue to show positive results. It also wants to determine whether tree cover improves sleep or children’s immune systems by encouraging outside play.

“There is no sort of ultimate proof,” Bhatnagar said. “But this is the strongest evidence of any study that’s ever been done on trees and their relationship to health.”

Growing evidence shows the importance of ensuring green spaces are equitably distributed around cities, which is currently not the case .

Casey said it’s important that city planners be careful not to create “green gentrification” when they create more equitable access to green spaces in cities — that is, when spaces such as water fronts are restored and housing prices increase as a result, making it unaffordable for current residents to continue living there once a green space is completed.

“The take-home message here is that nature is not an amenity; green spaces are not a perk for the wealthy. They are essential for us as human beings,” James said.

Kaitlin Sullivan is a contributor for NBCNews.com who has worked with NBC News Investigations. She reports on health, science and the environment and is a graduate of the Craig Newmark Graduate School of Journalism at City University of New York.

Anne Thompson is NBC News’ chief environmental affairs correspondent.

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Green Mountain Coffee's Bob Stiller Shares His Best Advice From 4 Decades of Business-Building

The longtime ceo reflects on building sustainability into his business--and how things fell apart..

Keurig Green Mountain founder Robert Stiller.

Bob Stiller, the longtime CEO of Green Mountain Coffee, always had an eye for offbeat opportunities. In the 1970s, he launched E-Z Wider rolling papers to cater to marijuana smokers who wanted wider rolling papers than what was already on the market. Stiller's timing was good, and when he sold the company in 1980, he personally pocketed $3.1 million.

As Stiller recounts in his forthcoming book Better & Better: Creating a Culture of Purpose, Excellence, and Transformative Human Engagement (out September 6 from McGraw Hill), during a ski trip in Vermont, he discovered Green Mountain Coffee Roasters. The cafe in Waitsfield, Vermont, roasted its own beans long before specialty coffee roasters were common, and Stiller's first sip of Green Mountain coffee was eye-opening. He spotted his next opportunity in Green Mountain's premium coffee beans and grounds, and bought and reincorporated the business in 1981.

Under Stiller, Green Mountain made environmental sustainability and community engagement a priority from the start--embracing the principles of corporate social responsibility (CSR) before many people talked about them. In 2000, the company became one of the first major coffee companies to join the Fair Trade movement, and it had a longstanding practice of donating 5 percent of its pretax profits to charitable causes.

But that didn't get in the way of success: The company went public on the Nasdaq in 1993, and as the stock price soared in the 2000s, many employees became millionaires. In 2006, Green Mountain bought single-serving coffee machine company Keurig. One year later, Stiller handed the CEO reins over to Larry Blanford, who had been an executive at large consumer brands.

In Stiller's telling, the pressures of rapid growth and a leadership transition seemed to erode the company's culture and values. The company was later subject to a short-selling campaign and criticized for the environmental impact of its single-serve K-cups. Stiller left the board in 2013, and in 2016, the company was bought for $13.9 billion and taken private by JAB Holding, which owns Peet's Coffee, among other brands.

In this conversation with Inc. , Stiller explains what he wishes he'd done differently, and why CSR still matters.

When Green Mountain was starting out in the 1980s, people weren't really talking about the environment and sustainability. How did you realize this was something that needed to be part of the business?

In the late '80s, a bunch of the employees wanted to start an environmental committee. They redesigned the shipping boxes and were much more conscious of energy. It created a passion in them, and they were much more engaged in the business and wanting to make a difference in the world. Later, our drivers developed a no-idle policy so we would save gas. If that was handed down from the top, how many people would do it? It's a different thing when it comes from the employees.

I always felt it was important to co-create something. If somebody shares in the deciding of what to do, they're much more bought into its success. I also saw that, when I had a great idea, whenever I shared that idea with someone, we improved it. The more people that you involve in something, the more creative the solution is going to be. The trick is having everybody understand what the mission is and the strategies of a company so that they realize they're a part of that and make a contribution.

When we started giving 5 percent of our pre-tax profits to causes, it became: the more money we make, the more good we are doing in the world. That was a lot more motivational to improve our processes and organization.

CSR goals and other things you pioneered became mainstream in the 2000s. Now they're under attack. What advice do you have for entrepreneurs trying to navigate this world right now?

If you look at CSR, what is it? It's taking care of your employees, your stakeholders, and the environment. A lot of these initiatives just make business sense. We donated coffee to nonprofits. Was that CSR or marketing? People who were tasting our coffee developed a relationship with it. If they like it, they go buy it, but they also appreciate that we care about what they're doing.

We looked through our supply chain for efforts that would help our business. There had to be some indirect connection, [such as] donating to a local food bank or working with the farmers and their communities. We gave everybody an hour off a week to volunteer. Some people built that up. This one guy took a week off and went to Costa Rica to work in a coffee community.

Look at areas your business touches and what can be done with that. You might help make your industry more effective. If you're starting a business, you depend on a lot of people in the community to support you. How can you support the community in return?

We got little pushback in the early '90s, when we went public. But I would make the case that it really drove our success. Torrey Project looked at companies for 20 years, and the ones that engage their stakeholders outperform the S&P by 100 percent. Somebody might say in the short term, this is a little more expensive, but the long-term benefits are dramatically better.

Green Mountain was known for generous education benefits. Why was that important to you?

Wages are generally one of the bigger expenses of a company. People always look for ways to cut the expense. I'm much more, yeah, it's your biggest expense, let's make it as effective as it can be: give them training, teach them meditation, teach them budgeting. I remember we even had babysitting classes.

What does that have to do with the business? It helps them be much more creative, a better person, and a better employee. There's no leaving your troubles at home and coming to work. I think really supporting of your employees, and then your stakeholders, it all makes sense. If you don't care about somebody, why should they care about you?

When the Keurig coffee makers took off, there was a lot of backlash to the trash generated by single-serving K-cups. Is there anything you would have done differently?

There was certainly an impact on the environment. We did everything we could to minimize that impact. We did a study to see what the impact was. If you looked at coffee waste, and the ramifications of that coffee waste with energy, crops, and transportation, it really was less of an impact.

I feel overall we made a positive impact with the company. It reminds me of when we were doing a lot of Fair Trade coffee. We got pushback from some Fair Trade companies: How could we sell regular coffee? I think you need to be successful as an organization, first and foremost. We needed to have a complete coffee offering. We got into [food services company] Sodexo with our regular coffee, and then a couple of years later, they switched to Fair Trade. You've got to do what's right to build the strength of your company.

Succession is a big concern for many founders. You write in your book that Keurig Green Mountain, as it was called at the time, lost its way when you brought in a new CEO. What should others do differently?

We were growing to be a multi-billion dollar company, and we wanted somebody with that experience. I was kind of burned out and very naive [to think] that the person I hired would work with me and do things my way. It didn't really occur to me they would want to take their own path. I never really did a search or figured out what the competencies should be.

In hindsight, I would do an Appreciative Inquiry summit with the company leadership and board, and ask everybody, why are we successful? What is it that drives our success? What areas might we do better? Really come up with a plan of how we want to go forward, and then get somebody that will accept that and believes in what we were doing versus having these practices being foreign to them.

It's amazing how often it doesn't work as well as you'd think. I would say onboarding--understanding what works and getting them to be really part of the team--is as important as finding somebody with the right experience. You need to be sure your company works for that person as well. Often people will just focus on what needs to get done and do it, versus thinking, I have to do it with this organization. The organization is the tool to do it.

A refreshed look at leadership from the desk of CEO and chief content officer Stephanie Mehta

How a Northeastern scientist is turning carbon dioxide into renewable ethanol

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Assistant professor Magda Barecka is designing a chemical reactor that could produce renewable, carbon-neutral ethanol for use in fuels. Her research recently received support from the U.S. Department of Energy.

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Magda Barecka is envisioning a world without fossil fuels.

An assistant professor of chemical engineering and chemistry and chemical biology at Northeastern University, Barecka says that the aim of her research is to enable “our society to function, to have all the chemicals that we need, without using fossil fuels.”

Like alchemists, Barecka and her team transform one thing into another — but instead of lead into gold, they transform carbon dioxide into ethanol.

After extracting carbon dioxide from the atmosphere and introducing it to a proprietary liquid in the base of their electrochemical reactor, a series of electrified metal plates do the transformative work, producing liquid ethanol that can be synthesized into a variety of fuels.

Despite its ability to burn — and thus serve as a fuel — ethanol is an alcohol and not a fossil fuel.

When it’s eventually burned, the ethanol will release carbon dioxide back into the atmosphere — but because that CO2 was originally taken from the air, the result is a carbon-neutral cycle.

Barecka and her team have published extensively on these topics, including here and here .

Their chemical reactor does require electricity, however, which still often comes from fossil fuel-based power plants.

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If the electricity required to make this conversion were to come from a renewable source, then the entire process could be made carbon neutral, a closed loop.

Now, Barecka’s research has received support from the U.S. Department of Energy through a program that supports projects that use “renewable energy sources like wind and solar to produce liquids for sustainable fuels or chemicals that can be transported and stored as easily as carbon-intensive liquids like gasoline or oil.”

“It takes a relatively long time to connect a new, renewable power plant to the grid,” Barecka says, which “could deliver energy, renewable energy, [with a] very low carbon footprint,” and they come with their own logistical and financial complications.

Working with the Department of Energy, Barecka and her team are “looking into what is the most efficient way to use this renewable electricity. So we really care about the amount of the product that we can get by using a specific amount of electricity coming from a renewable plant.”

Using electricity from a renewable power plant “to drive any chemical reactions,” she says, “we could really overcome the main bottleneck that we see right now in the construction of new renewable power plants.

“There’s a very interesting synergy, that by providing a technology that uses renewable electricity, we can ultimately help to have more renewable power plants in general.

“We want to create something that will unlock many different possibilities, that you can get many things that our society needs” without putting more greenhouse gases into the air, Barecka says.

Jet fuel is just one of the applications ethanol can be employed for.

The aviation market, Barecka continues, “is very customer oriented, and they take very seriously the fact that people are starting to be very careful about the carbon footprint of their travels.”

The aviation market already has “an existing method to synthesize fuels that use ethanol,” she says. “So that’s a great thing that we’re doing, really plugging into something existing so it can have a broader impact.”

“Whatever we develop, we want it to be applicable in the real-life scenario,” she says. “So that means that it has to fit into an existing supply chain.”

“I do recognize that there are a lot of logistics and multiple factors beyond science that are involved” in shifting away from fossil fuel reliance, Barecka says. “But I do believe that if we think deeply and differently about how we perform chemical reactions, we do have opportunities to use different energy sources.

“We can use those energy sources efficiently, and there is nothing from a thermodynamic point of view that prevents us from using different carbon sources than fossil fuels.”

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Starbucks New Fall Merchandise

August 21, 2024 • 2 min read

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Alongside the return of the iconic Pumpkin Spice Latte, Starbucks is falling into the fall state of mind with new drinkware. From multicolored cold cups to tumblers in vibrant autumn hues, this cozy collection will be available in participating U.S. stores starting August 22 for a limited time, while supplies last.

And, Starbucks® Rewards members who bring a clean, personal cup will earn 25 Stars in addition to 10 cents off their beverage* – whether they order in café, on the Starbucks® app, or in the drive-thru.

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Deep Purple Shine Tumbler (20 oz)

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Harvest Gradient Cold Cup (24 oz)

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Midnight Blue Twist-to-Sip Water Bottle (20 oz)

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COMMENTS

Supplementation of green coffee bean extract in healthy overweight subjects increases lean mass/fat mass ratio: A randomized, double-blind clinical study
In a crossover study, green coffee bean extract was administered to the subjects at high (350 mg three times a day) and low (250 mg twice a day) doses for 6 weeks with a 2-week washout period between the treatments. 24 This study concluded that the extract was more efficacious in reducing the weight than the FDA-approved drugs. The limitations ...
Chlorogenic acid in green bean coffee on body weight: a systematic
The caffeine and other chemical components in green bean coffee come from raw, unroasted coffee beans. According to our research, GBCE with 500 mg/day of CGA reduces body weight. Multiple comprehensive analyses of clinical studies have demonstrated that GBCE supplementation can encourage weight reduction, lower obesity, fasting blood glucose ...
New WCR Research Outlines 'Innovation Crisis' in Green Coffee
The paper characterizes the $452 million financial benchmark as an "investment gap" and says that the global green coffee sector is facing an "innovation crisis.". " coffee plant " by functoruser is licensed under CC BY 2.0. The research behind the paper was led by Dr. Mywish Maredia, a professor of development economics in the ...
The effect of green coffee extract supplementation on cardio metabolic
Method. A systematic literature search was performed throughout the PubMed, Embase, Scopus, and Web of Science databases up to October 2019. As a result, all randomized controlled trials over the effect of green coffee supplementation on fasting blood sugar (FBS), insulin, triglyceride, high-density lipoprotein (HDL), low-density lipoprotein (LDL), C - reactive protein (CRP), and homeostatic ...
Cell-based coffee future-proofs world's favorite brew
The company adds natural flavors taken from coffee byproducts to the resulting green coffee powder, which they dry and roast like coffee beans. Another startup, California Cultured, is applying ...
Green Coffee: Benefits, Weight Loss, and Side Effects
Green coffee is an increasingly popular beverage and weight loss supplement. ... Most human research on green coffee has been inconclusive. ... A new study found that 60% of baby foods in the U.S ...
The effects of green coffee extract supplementation on glycemic indices
The role of coffee consumption in the risk of cardiovascular diseases has been debated for many years. The current study aimed to summarize earlier evidence on the effects of green coffee extract (GCE) supplementation on glycemic indices and lipid profile. We searched available online databases for relevant clinical trials published up to October 2019.
Green Coffee for Pharmacological Weight Loss
Conclusion. Current literature regarding green coffee for the use of weight loss is limited to 4 small clinical trials. All studies found statistically significant reductions in weight compared to baseline or a direct comparator. However, in most studies, the clinical significance of this reduction was minimal.
The effect of green coffee extract supplementation on obesity indices
Data pooled from 5 eligible papers revealed that green coffee extract can reduce BW (WMD: −1.22 kg, ... This research was funded by Traditional Chinese Medicine Research Project of Health Commission of Hubei Province (No. ZY2021M017), Hubei University of Chinese Medicine Funds for Distinguished Young Scholars (No. 2022ZZXJ004), Xinjiang ...
Green Coffee Bean Extract Risks and Benefits
Frequent urination. Headaches. Increased heart rate. Trouble sleeping. Upset stomach. Because the U.S. Food and Drug Administration (FDA) doesn't regulate supplements, Czerwony says it's ...
The Potentials of Green Coffee Proteins as New Functional Food
Proteins/enzymes, peptides and free amino acids in green coffee beans are the main contributors to the development of coffee flavor and quality during roasting, as a result of the Maillard reaction, and are ultimately responsible for the formation of the coffee aroma. Only 0.15-2.5% of free amino acids are present in the green beans. A crude protein content of 8.5 to 12% after correction for ...
Green Coffee: Uses and Risks
Some research shows green coffee may help with weight loss. A few small studies found that people taking green coffee lost 3 to 5 pounds more than people who weren't. Green coffee may act by ...
The use of green coffee extract as a weight loss supplement: a
The purpose of this paper is to assess the efficacy of green coffee extract (GCE) as a weight loss supplement, using data from human clinical trials. Electronic and nonelectronic searches were conducted to identify relevant articles, with no restrictions in time or language. Two independent reviewers extracted the data and assessed the ...
Research Breakdown on Green Coffee Extract
Chlorogenic Acid compounds, which are small phenolics bound to Quinic Acid; commonly seen as the main active component of Green Coffee Extract [1] with about 7-12g per 100g before processing and up to 42.2% of all phenolics. [2] The major chlorogenic acids appear to be dicaffeoylquinic (3,4-, 3,5-, and 4,5) and all caffeoyl, feruloyl, and p-coumaroyl quinic acids at 3-, 4-, and 5- positions ...
Are coffee pods better for the environment than you thought? New
But new research suggests they might be greener than using a traditional coffee maker. It is estimated that around two billion cups of coffee are consumed globally each day, with Europe accounting ...
The Use of Green Coffee Extract as a Weight Loss Supplement: A
However, there is limited clinical trials evidence of efficacy and safety of GBCE and CGA on body weight in long-term studies. Onakpoya et al. (2010) showed the efficacy of green coffee extract ...
Nestlé on developing future-proof coffee
As some of the world's largest coffee roasters, Nestlé has skin in the game when it comes to the future of the coffee-farming industry. Each year, the parent company purchases around 13 million bags of green coffee from 20 countries for its brands Nescafé, Nespresso, and Starbucks Coffee at Home, sourcing from and working alongside hundreds of thousands of smallholder coffee farmers.
The science of coffee
The latest research on caffeine reveals why coffee and decaf can be so good for your health, but energy drinks can be lethal By Jasmin Fox-Skelly 20 August 2024
A cautionary tale for Starbucks: Green Mountain Coffee's
Robert Stiller is the founder of Green Mountain Coffee and the author of "Better and Better: Creating a Culture of Purpose, Excellence, and Transformative Human Engagement." Courtesy of Robert ...
Is caffeine damaging to heart health?
New research, presented at American College of Cardiology's ACC Asia 2024 suggests that consuming over 400 milligrams of caffeine each day could increase the risk of cardiovascular disease. The study, which analysed the effects of caffeine on young, 'healthy' adults, found that regular intake at this level disrupts the autonomic nervous ...
7-Eleven Rocks Out With Exclusive Coffee Blend Collaboration
To celebrate the launch, 7-Eleven and Punk Bunny will give fans a chance to win free coffee. On Aug. 28, starting at 8 a.m. ET, the first 50 fans to show up at 7-Eleven at 800 6th Ave. in New York ...
The Use of Green Coffee Extract as a Weight Loss Supplement: A
GCE is present in green or raw coffee . It is also present in roasted coffee, but much of the GCE is destroyed during the roasting process. Some GCE constituents, such as chlorogenic acid (CGA) can also be found in a variety of fruits and vegetables . The daily intake of CGA in persons drinking coffee varies from 0.5 to 1 g .
Sensory analysis of the flavor profile of full immersion hot, room
The importance of TDS and E on sensory quality and consumer liking of coffee has been well established 1,2,3,4,5.While most coffee sensory studies of brewed coffee focused on pressurized espresso ...
Announcing the Michelman Green, Clean, and Sustainable Technology
Courtesy of the generous contributions of the Dr. John S. Michelman Fund for the Advancement of Sustainable Technology, the Michelman Green, Clean, and Sustainable Technology Research Innovation Program supports applied R&D and use-inspired research with the potential to meaningfully contribute to improvements in environmental health, environmental stewardship, and sustainability by ...
1 Million Cups
A weekly event for local entrepreneurs to meet, present their startups, and gain feedback from the thriving peer network of St. Petersburg's local business community. The Greenhouse hosts 1 Million Cups St. Petersburg from 9 to 10 a.m. every Wednesday morning. The format of these caffeinated events is simple; a presenter pitches their ...
Living in tree-filled areas may reduce heart disease risk, study shows
Tree-filled neighborhoods may reduce heart disease risk, new research shows. More than 8,000 trees were planted in areas of South Louisville, Kentucky as part of a research trial.
The Greenhouse
I try to tell any new or prospective entrepreneurs about it. Free support from enthusiastic, caring and helpful people! Who wouldn't want that? Janell. Vet 2 Door. 2020 STATS. Client Engagements. Entrepreneurs Served. Total Events. Coffee Cups. View the full 2020 Annual Report. facebook; instagram; x; 440 2nd Avenue North, St. Petersburg, FL ...
Green Mountain Coffee's Bob Stiller Shares His Best Advice From 4
In 2006, Green Mountain bought single-serving coffee machine company Keurig. One year later, Stiller handed the CEO reins over to Larry Blanford, who had been an executive at large consumer brands.
How Green Energy Research Is Shaping a Fossil Fuel-Free Future
Now, Barecka's research has received support from the U.S. Department of Energy through a program that supports projects that use "renewable energy sources like wind and solar to produce liquids for sustainable fuels or chemicals that can be transported and stored as easily as carbon-intensive liquids like gasoline or oil."
Starbucks New Fall Merchandise
Alongside the return of the iconic Pumpkin Spice Latte, Starbucks is falling into the fall state of mind with new drinkware. From multicolored cold cups to tumblers in vibrant autumn hues, this cozy collection will be available in participating U.S. stores starting August 22 for a limited time, while supplies last.

New WCR Research Outlines ‘Innovation Crisis’ in Green Coffee

The effects of green coffee extract supplementation on glycemic indices and lipid profile in adults: a systematic review and dose-response meta-analysis of clinical trials

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The effect of GCE on serum concentrations of TG

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The effect of GCE on serum concentrations of LDL

The effect of GCE on serum concentrations of HDL

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