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Anthocyanins are flavonoids that have been suggested to provide beneficial health effects. The biological activity of anthocyanins is influenced by their pharmacokinetic properties, but anthocyanins are associated with limited bioavailability in humans. In the presented study, we investigated how the encapsulation of bilberry extract (BE), a source of anthocyanins, with either whey protein or citrus pectin influences the bioavailability and intestinal accessibility of anthocyanins in humans. We performed an intervention study that analyzed anthocyanins and their degradation products in the urine, plasma, and ileal effluent of healthy volunteers and ileostomists (subjects without an intact colon). We were able to show, that whey protein encapsulation modulated short-term bioavailability and that citrus pectin encapsulation increased intestinal accessibility during passage through the small intestine and modulated the formation of the degradation product phloroglucinol aldehyde (PGAL) in human plasma.

We investigated the importance of the large intestine on the bioavailability of anthocyanins from bilberries in humans with/without a colon. Low bioavailability of anthocyanins in plasma and urine was observed in the frame of this study. Anthocyanins reached the circulation mainly as glucuronides. Analysis of ileal effluents (at end of small intestine) demonstrated that 30% of ingested anthocyanins were stable during 8h passage through the upper intestine. Only 20% degradants were formed and mostly intact anthocyanins were absorbed from the small intestine. Higher amounts of degradants than anthocyanins reached the circulation after bilberry extract consumption in both groups of subjects. Comparison of the bioavailability of anthocyanins in healthy subjects versus ileostomists revealed substantially higher amounts of anthocyanins and degradants in the plasma/urine of subjects with an intact gut. The results suggested that the colon is a significant site for absorption of bioactive components such as anthocyanins and their degradation products.

The incidence of chronic diseases increases with advancing age of the population. A commonly discussed cause of chronic diseases is oxidative stress, which occurs in the body when there is an imbalance between the formation and inactivation of so-called reactive oxygen species (ROS). Epidemiological data suggest that a 'healthy diet', with a high content of flavonoids indicates preventive properties and correlates with an inverse effect with respect to the risk of chronic diseases. Berries (especially bilberries, Vaccinium myrtillus L.) are an important source of these flavonoids. In this study, we investigated, in vitro, the antioxidative properties of fractions obtained from a commercially available anthocyanin-rich bilberry extract (BE). As markers for antioxidative activity, the intracellularly generated ROS levels, oxidative DNA damage, and total glutathione (tGSH) levels were determined in the human colon cell lines Caco-2 and HT-29. In Caco-2 cells, the ROS levels and, in both cell lines, the oxidative DNA damage, were significantly reduced in the presence of the original BE and phenolcarbonic acid-rich fraction. Total GSH levels were slightly increased after pretreatment with BE, phenolcarbonic acid and the polymeric fractions, but not with the anthocyanin fraction. In summary, the BE and the therefrom-isolated phenolcarbonic acid-rich fraction, showed the most potent antioxidative activity whereas the polymeric and anthocyanin-rich fraction, in total, were less active.

Scope Obesity has been found to be associated with low grade inflammation accompanied by chronic oxidative stress. The transcription factor Nrf2 is likely involved in lipid metabolism and inflammation processes, possibly mediated by an antioxidant response element (ARE)-similar region located in the promoter of lipogenic genes like peroxisome-proliferator activated receptor γ (PPARγ) and pro-inflammatory interleukin 6 (IL6). The present study investigates the influence of coffee consumption on the transcription of obesity-associated genes in human peripheral blood lymphocytes (PBL). Two different coffee blends with comparable caffeine concentrations were provided, rich either in chlorogenic acids and trigonelline (market blend, MB) or in N-methylpyridinium (NMP, study blend, SB). Methods and results In a cross-over randomized double blind intervention study 84 volunteers (male and female, 25.6 ± 5.8 years, BMI 22.9 ± 1.9 kg/m2, healthy, nonsmokers, regular coffee drinker) daily consumed 750 mL of the respective coffee over a period of 4 weeks, respectively. Transcription of IL6 in PBL was found to be positively associated with body fat. In the first intervention period consumption of MB decreased significantly the transcription of Nrf2, PPARγ and IL6 while concomitantly an enhanced level of PPARα mRNA was found. Due to carry-over effects for Nrf2 and PPARα, data of both intervention periods could only be pooled for PPARγ and IL6. Pooled data from both intervention periods showed a significant decrease of IL6 transcripts for SB consumption only. The changes in gene transcription appear to correlate with the level of different CGA metabolites in the plasma of the volunteers. Initial results further indicate a potential contribution of genetic polymorphisms in the nrf2 promoter and the pparγ-gene to the influence of coffee consumption on PPARγ transcription. Conclusion Regular coffee consumption affects the transcription of genes associated with obesity and/or inflammation. Metabolites of chlorogenic acids as well as genetic polymorphisms may be relevant influencing factors.

Hydroxycinnamates are secondary plant metabolites and ubiquitous constituents of plant materials, including many foods and beverages. Hydroxycinnamates are most often conjugated with d -quinic acid, giving rise to the substance class of chlorogenic acids (CGAs). Coffee beans contain high levels of CGAs and are therefore considered the richest dietary source of this substance class. CGAs have been shown to have several beneficial health properties, including antioxidant activity, anticarcinogenic and antidiabetic potential. However, their positive effects on human health highly depend on their bioavailability. In the present study, we investigated the intestinal absorption of hydroxycinnamates using the human colon carcinoma cell line Caco-2, serving as an in vitro model for intestinal absorption. Physiological conditions were modeled using the dynamic Ussing chamber model to simulate apical/basolateral compartments of the mucosa. The test substances (5-O-caffeoylquinic acid (5-CQA), caffeoylquinic acid lactones (CQLs), caffeic (CA) and ferulic acid (FA)) were added individually to the apical compartment of the chamber to physiological concentrations. Structure-dependent absorption was observed, resulting in higher absorption efficiency for FA (12.5 ± 1.0%; 100 μM) than CA (0.33 ± 0.13%; 100 μM). A low absorption rate for 5-CQA (0.1 ± 0.08%; 100 μM) was in line with the existing literature. CQA and CQL-isomers showed comparable absorption efficiencies at 100 μM (0.07 ± 0.02%). Concentration-dependent absorption of the more hydrophobic CQLs, as well as their precursor 5-CQA, was found to be non-saturable, indicating a passive diffusion process. Overall, our results indicated that the absorption rates of hydroxycinnamates are substantially influenced by their physicochemical properties.

Recent epidemiological studies suggest that coffee, one of the most widely consumed beverages worldwide, may reduce risks of degenerative diseases such as diabetes type 2, cardiovascular disease and certain types of cancer. These effects have partly been ascribed to coffee's antioxidant and body weight-reducing capacities. To explore the mechanisms involved, effects of coffee consumption on body weight/composition, food intake, satiety markers (serotonin and ghrelin) and DNA integrity were monitored in a four-week double-blind randomized crossover intervention study with 84 healthy subjects. Subjects consumed two different coffee blends (study blend, SB, and market blend, MB), with similar caffeine contents but substantially differing contents of chlorogenic acids and N-methylpyridinium. The consumption of both coffees (3 × 250 mL per day) was associated with a decrease in body fat over the whole study period (p

In the presented study the effects of key brewing parameters (temperature, holding time and storage conditions of coffee powder) on 12 alkylpyrazines in coffee beverages were investigated. The results show that the alkylpyrazine profiles of coffee beverages are similar to those of the coffee used. In total, 70–82% of the alkylpyrazines (113.3 ± 3.5 to 132.6 ± 0.6 mg/kg), depending on the brewing method, passed into beverages during the brewing process. At temperatures higher than 50 °C the alkylpyrazine contents of coffee beverages were almost independent of the brewing temperature. During a 30 min holding time at room temperature the alkylpyrazine contents of a freshly brewed cup of coffee decreased by about 10%. Furthermore, storing coffee in closed systems for up to 29 days at +4 °C, −20 °C or room temperature (+22 °C) had minor effects on the alkylpyrazine contents of beverages produced from the coffee. The results show that under customary conditions more than 70% of the alkylpyrazines present in ground coffee are transferred to beverages during the brewing process. Estimated total amounts of alkylpyrazines ingested by the consumer per cup of coffee beverage are in the milligram range, sufficient to have significant potential health effects.

Scope This study intended to clarify whether two coffee brews, a market blend (MB) and a study blend (SB), containing equal amounts of caffeine, but differing in their contents of N-methylpyridinium, trigonelline and chlorogenic acids, differentially affect blood lipid profiles and glucose concentrations as well as blood platelet phosphodiesterase and lymphocyte energy charge potential in healthy volunteers. Methods and results In this double-blinded, randomized, controlled cross-over intervention study, 84 healthy normal-weight female and male volunteers consumed 750 mL of medium roast MB and dark roast SB coffee per day for 4 weeks. Following MB and SB coffee intervention, plasma free fatty acid concentrations equally increased (p Conclusion The results of this intervention study indicate that MB and SB coffees, although differing in contents of N-methylpyridinium, trigonelline and chlorogenic acids, largely exert similar biological effects as monitored by the biomarkers tested.

The application of antioxidative phenolic plant compounds, such as bilberry anthocyanins, as bioactive food additive may be facilitated by the protection through microencapsulation. The antioxidant capacity of the encapsulated compounds could thus be preserved until the point of action is reached. In this study, whey protein-based microcapsules loaded with an anthocyanin-rich bilberry extract were generated thermally after forming droplets by the emulsion method. The TEAC (Trolox equivalent antioxidant capacity)-assay was used to assess the antioxidant capacity of the anthocyanin-rich bilberry extract during all steps of the microencapsulation process. It could be shown that the loss of antioxidant capacity during microencapsulation can mainly be attributed to interactions between the whey proteins and bilberry extract compounds other than anthocyanins. An anthocyanin-attributed loss of antioxidant capacity occurred when an emulsifier was used in the microencapsulation process. In this case, a transition of hydrophilic anthocyanins to the oil phase was observed. Eventually, the generated bilberry-extract loaded microcapsules were investigated in terms of their release behaviour in digestive media. Due to the time-dependent diffusive release from the microcapsules, the degradation of anthocyanins at pH 6.8 was retarded in comparison to non-encapsulated bilberry-anthocyanins. However, anthocyanin degradation at pH 6.8 was minimal when the non-gelled bilberry extract–whey protein solution was incubated which indicates a protective effect of native whey proteins. The results of this study provide new insights regarding protein-based microencapsulation of phenolic compounds and are thus of relevance for the development of innovative encapsulation systems.

Human studies provide evidence for beneficial effects of polyphenol-rich foods on cardiovascular health. The antioxidant activity of polyphenols potentially explains these effects, but is the antioxidant activity a reliable predictor for these effects? An International Life Sciences Institute Europe working group addressed this question and explored the potential of antioxidant claims for polyphenols in relation to cardiovascular health by using the so-called Process for the Assessment of Scientific Support for Claims on Foods project criteria. In this process, analytical aspects of polyphenols, their occurrence in foods, dietary intake, and bioavailability were reviewed. Human studies on polyphenols and cardiovascular health were reviewed together with methods for biomarkers of oxidative damage and total antioxidant capacity (TAC). In retrospective studies, F2-isoprostanes and oxidized LDL, the most reliable biomarkers of lipid peroxidation, and measures for TAC showed the expected differences between cardiovascular disease patients and healthy controls, but prospective studies are lacking, and a causal relationship between these biomarkers and cardiovascular health could not be established. Therefore, the physiological relevance of a potential change in these biomarkers is unclear. We found limited evidence that some types of polyphenol-rich products modify these biomarkers in humans. A direct antioxidant effect of polyphenols in vivo is questionable, however, because concentrations in blood are low compared with other antioxidants and extensive metabolism following ingestion lowers their antioxidant activity. Therefore, the biological relevance of direct antioxidant effects of polyphenols for cardiovascular health could not be established. Overall, although some polyphenol-rich foods exert beneficial effects on some biomarkers of cardiovascular health, there is no evidence that this is caused by improvements in antioxidant function biomarkers (oxidative damage or antioxidant capacity).

Using extracts obtained by simultaneous distillation extraction (SDE) as well as liquid liquid extraction (LLE) of self-prepared juices from pear fruits ( n = 20) and from commercial pear products (juices, n = 11; brandies, n = 16; baby food, n = 8), on-line capillary gas chromatography–isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the δ 13 C V-PDB and δ 2 H V-SMOW values of major pear flavour constituents. In addition to butyl acetate 1 , 1-butanol 2 , hexyl acetate 3 , 1-hexanol 4 , as well as the ‘pear esters’ methyl E , Z -2,4-decadienoate 5 , ethyl E , Z -2,4-decadienaote 6 , and ethyl E , E -2,4-decadienoate 7 , each originating from the fruit, the δ 13 C VPDB and δ 2 H V-SMOW data of commercial synthetic and “natural” (biotechnologically derived) 1 – 7 were determined.

Synthesis of six new flavor sulfates (benzyl sulfate, 2-phenylethyl sulfate, 2,5-dimethyl-4-hydroxy-3(2H)-furanone sulfate, α-ionol sulfate, vomifoliol sulfate, linalyl sulfate) was performed in order to screen for these compounds in plants. Structural elucidation was performed by NMR spectroscopy and a screening method developed by using high performance liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC–ESI–MS/MS). The results obtained with various plant tissues indicate that sulfation of flavor compounds is a common pathway in plant metabolism.