The roasting process does not influence the extent of conjugation of coffee chlorogenic and phenolic acids

Sustained Consumption of a Decaffeinated Green Coffee Nutraceutical Has Limited Effects on Phenolic Metabolism and Bioavailability in Overweight/Obese Subjects

Knowledge on the bioavailability of coffee (poly)phenols mostly come from single dose postprandial studies. This study aimed at investigating the effects of regularly consuming a green coffee phenolic extract (GCPE) on the bioavailability and metabolism of (poly)phenols. Volunteers with overweight/obesity consumed a decaffeinated GCPE nutraceutical containing 300 mg hydroxycinnamates twice daily for two months. Plasma and urinary pharmacokinetics, and fecal excretion of phenolic metabolites were characterized by LC-MS-QToF at weeks 0 and 8. Fifty-four metabolites were identified in biological fluids. Regular consumption of the nutraceutical produced certain changes: reduced forms of caffeic, ferulic and coumaric acids in urine or 3-(3′-hydroxypenyl)propanoic, and 3,4-dihydroxybenzoic acids in feces significantly increased (p < 0.05) after 8 weeks; in contrast, coumaroylquinic and dihydrocoumaroylquinic acids in urine decreased (p < 0.05) compared to baseline excretion. The sum of intestinal and colonic metabolites increased after sustained consumption of GCPE, without reaching statistical significance, suggesting a small overall effect on (poly)phenols’ bioavailability.

Technological and Biotechnological Processes To Enhance the Bioavailability of Dietary (Poly)phenols in Humans

The health effects of (poly)phenols (PPs) depend upon their bioavailability that, in general, is very low and shows a high interindividual variability. The low bioavailability of PPs is mainly attributed to their low absorption in the upper gastrointestinal tract as a result of their low water solubility, their presence in foods as polymers or in glycosylated forms, and their tight bond to food matrices. Although many studies have investigated how technological and biotechnological processes affect the phenolic composition of fruits and vegetables, limited information exists regarding their effects on PP bioavailability in humans. In the present review, the effect of food processing (mechanical, thermal, and non-thermal treatments), oral-delivery nanoformulations, enzymatic hydrolysis, fermentation, co-administration with probiotics, and generation of postbiotics in PP bioavailability have been overviewed, focusing in the evidence provided in humans.

Acute dose-response effect of coffee-derived chlorogenic acids on the human vasculature in healthy volunteers: a randomized controlled trial

BACKGROUND

Epidemiological studies have reported lower risk of cardiovascular disease with moderate coffee consumption. In addition, emerging evidence indicates that consumption of coffee beverages enriched in chlorogenic acids (CGAs) may influence blood pressure and endothelial function, suggesting that the beneficial cardiovascular effect of coffee may relate to its CGA content.

OBJECTIVES

We conducted a double-blind randomized crossover trial to test the effect of acute consumption of a decaffeinated green coffee extract (DGCE), rich in CGAs, on endothelial function in healthy subjects.

METHODS

We compared 3 different doses of DGCE (302, 604, and 906 mg, respectively) with a placebo. Endothelial function was defined as the percentage change in the internal diameter of the brachial artery in response to flow-mediated dilation (%FMD). In addition, we followed the plasma concentration-time profiles of 25 systemic CGA metabolites over 24 h after DGCE consumption and we explored the relation between systemic concentrations of CGAs and the effect on %FMD.

RESULTS

The DGCE formulations containing different amounts of CGAs resulted in dose-proportional increases in overall total polyphenol concentrations. The systemic appearance of total CGAs was biphasic, in agreement with previous results suggesting 2 sites of absorption in the gastrointestinal tract. Compared with the placebo group, a significant FMD increase (>1%) was observed 8.5, 10, and 24 h after consumption of 302 mg DGCE (∼156.4 mg CGAs). The differences with placebo observed in the other 2 groups were not statistically significant. Evaluation of the relation between phenolic exposure and %FMD showed a positive tendency toward a larger effect at higher concentrations and different behavior of CGA metabolites depending on the conjugated chemical position.

CONCLUSIONS

We demonstrated an acute improvement in %FMD over time after ingestion of a DGCE, explained at least partly by the presence in the blood circulation of CGAs and their metabolites. This trial was registered at clinicaltrials.gov as NCT03520452.

Consumption of Chlorogenic Acids through Coffee and Health Implications

Chlorogenic acids (CGA) are the main antioxidant compounds in the Western diet, due to their high concentrations in coffee associated with the high consumption of the beverage. Until about 10 years ago, like many other phenolic compounds, CGA were thought to be poorly absorbed in the human digestive system. Along the years, large amounts of information on the absorption and metabolism of these compounds have been unveiled, and today, it is known that, on average, about one third of the consumed CGA from coffee is absorbed in the human gastrointestinal tract, although large inter-individual variation exists. Considering results from in vitro animal and human studies, it is possible to conclude that the antioxidant and anti-inflammatory effects of coffee CGA are responsible for, at least to a certain extent, the association between coffee consumption and lower incidence of various degenerative and non-degenerative diseases, in addition to higher longevity.

Farm to Consumer: Factors Affecting the Organoleptic Characteristics of Coffee. II: Postharvest Processing Factors

The production and consumption of coffee are increasing despite the roadblocks to its agriculture and global trade. The unique, refreshing, and stimulating final cupping quality of coffee is the only reason for this rising production and consumption. Coffee quality is a multifaceted trait and is inevitably influenced by the way it is successively processed after harvesting. Reportedly, 60% of the quality attributes of coffee are governed by postharvest processing. The current review elaborates and establishes for the first time the relationship between different methods of postharvest processing of coffee and its varying organoleptic and sensory quality attributes. In view of the proven significance of each processing step, this review has been subdivided into three sections, secondary processing, primary processing, and postprocessing variables. Secondary processing addresses the immediate processing steps on the farm after harvest and storage before roasting. The primary processing section adheres specifically to roasting, grinding and brewing/extraction, topics which have been technically addressed more than any others in the literature and by industry. The postprocessing attribute section deals generally with interaction of the consumer with products of different visual appearance. Finally, there are still some bottlenecks which need to be addressed, not only to completely understand the relationship of varying postharvest processing methods with varying in-cup quality attributes, but also to devise the next generation of coffee processing technologies.

Bioavailability of hydroxycinnamates in an instant green/roasted coffee blend in humans. Identification of novel colonic metabolites

Roasting greatly reduces the phenolic content in green coffee beans. Considering the beneficial effects of coffee polyphenols, blends containing green coffee beans are being consumed as a healthier alternative to roasted coffee. This study was aimed at assessing the absorption and metabolism of hydroxycinnamates in an instant green/roasted (35/65) coffee blend in healthy humans. Twelve fasting men and women consumed a cup of coffee containing 269.5 mg (760.6 μmol) of chlorogenic acids. Blood and urine samples were taken before and after coffee consumption at different times and analyzed by LC-MS-QToF. Up to 25 and 42 metabolites were identified in plasma and urine, respectively, mainly in the form of sulfate and methyl derivatives, and to a lower extent as glucuronides. Un-metabolized hydroxycinnamate esters (caffeoyl-, feruloyl-, and coumaroylquinic acids), hydroxycinnamic acids (caffeic, ferulic and coumaric acids) and their phase II metabolites, in addition to phase II derivatives of lactones, represented a minor group of metabolites (16.3% of the metabolites excreted in urine) with kinetics compatible with small intestine absorption. Dihydrohydroxycinnamic acids and their phase II derivatives, in addition to feruloylglycine, showed delayed kinetics due to their colonic origin and represented the most abundant group of metabolites (75.7% of total urinary metabolites). Dihydrohydroxycinnamate esters (dihydroferuloyl-, dihydrocaffeoyl- and dihydrocoumaroylquinic acids) have been identified for the first time in both plasma and urine, with microbial origin (excreted 8-12 h after coffee intake) amounting to 8% of total urinary metabolites. In conclusion, coffee polyphenols are partially bioavailable and extensively metabolized, mainly by the colonic microbiota.