Antioxidant Characterization and Biological Effects of Grape Pomace Extracts Supplementation in Caenorhabditis elegans.

The aim of this work was to evaluate the biological activity of four grape pomace (GP) extracts that are rich in polyphenols using C. elegans as an in vivo model. Different concentrations of the GP extracts were assessed for their effects on the resistance of C. elegans against thermally induced oxidative stress, accumulation of reactive oxygen species (ROS), and lifespan. The cultivation of C. elegans with relatively low concentrations of GP extracts increased their resistance against thermal stress and prolonged their lifespan, while high levels displayed detrimental effects. In the studied extracts, maximum protection was observed for levels of polyphenols around 7 to 9 µg gallic acid equivalents per cultivation plate. The obtained results suggested that small changes in the ROS levels could have beneficial effects, although further studies are required to fully understand the impact of the extracts and assayed doses on ROS levels to explain the mechanism that is involved in the observed effects.

Chemical characterization and in vitro colonic fermentation of grape pomace extracts.

BACKGROUND: Currently, there is growing interest in extracts derived from winery by-products because of their beneficial health properties, which are associated with the presence of bioactive compounds. In this paper, we have carried out the chemical characterization and in vitro colonic fermentation of four grape pomace (GP) extracts rich in polyphenols and dietary fibre. RESULT: Firstly, phenolic and dietary fibre composition of the GP extracts was determined. The highest individual phenolic concentrations corresponded to gallic and ellagic acids, followed by catechins and flavonols. The non-digestible fibre fraction ranged from 66% to 83% of the GP extracts, which indicated that they mainly contained non-digestible cell wall components. Secondly, when GP extracts were subjected to fermentation by faecal microbiota, a total of 16 bacterial phenolic metabolites were found in the fermented samples, confirming that polyphenols contained in the GP extracts were metabolized to different active metabolites by microbiota. In addition, the GP extracts tended to promote the growth of intestinal microbiota, although it was only significant for the Enterococcus group. CONCLUSION: These findings, together with other information available in the literature, support the high added value of products obtained from winery by-products. © 2016 Society of Chemical Industry.

The food matrix affects the anthocyanin profile of fortified egg and dairy matrices during processing and in vitro digestion.

The aim of the present study was to understand to what extent the inclusion of anthocyanins into dairy and egg matrices could affect their stability after processing and their release and solubility during digestion. For this purpose, individual and total anthocyanin content of four different enriched matrices, namely custard dessert, milkshake, pancake and omelettete, was determined after their manufacturing and during in vitro digestion. Results showed that anthocyanin recovery after processing largely varied among matrices, mainly due to the treatments applied and the interactions developed with other food components. In terms of digestion, the present study showed that the inclusion of anthocyanins into food matrices could be an effective way to protect them against intestinal degradation, and also the incorporation of anthocyanins into matrices with different compositions and structures could represent an interesting and effective method to control the delivery of anthocyanins within the different compartments of the digestive tract.

Stability and bioaccessibility of anthocyanins in bakery products enriched with anthocyanins.

Anthocyanins, water soluble polyphenols, have been associated with several beneficial health effects. The aim of this study was to determine how the baking process and food matrix affect anthocyanin stability and bioaccessibility in bakery products in order to develop functional foods. Three well known regularly consumed bakery products (buns, breadsticks and biscuits) were enriched with anthocyanin (AC) isolated from grape skin alone or in combination with docosahexaenoic acid (AC + DHA) to reveal knowledge on AC as active ingredients in real food systems rather than pure compounds. Anthocyanin amounts added to the formulations of buns, breadsticks and biscuits were 34 mg per 100 g, 40 mg per 100 g and 37 mg per 100 g, respectively. The effect of processing, storage and the food matrix on AC stability and bioaccessibility was investigated. In addition, the sensory properties of bakery products were evaluated. Breadsticks enriched with AC and AC + DHA received the lowest scores in the pre-screening sensory test. Therefore breadsticks were excluded from further analysis. AC retentions, which were monitored by determination of malvidin 3-O-glucoside, in the bun and biscuit after baking were 95.9% (13.6 mg per 100 g) and 98.6% (15.2 mg per 100 g), respectively. Biscuits and buns enriched only with AC showed significantly higher anthocyanin bioaccessibilities (57.26% and 57.30%, respectively) than the same ones enriched with AC + DHA. AC stability in enriched products stored for 21 days was significantly lower than in products stored for 7 days (p < 0.05). However, this loss can be accepted as negligible since more than 70% of AC was retained in all the products.

Specific phenolic compounds and sensory properties of a new dealcoholized red wine with pomegranate (Punica granatum L.) extract.

The pomegranate (Punica granatum L.) fruit has a long history of human consumption and possesses notable antioxidant and cardiovascular properties. This work evaluated the feasibility to provide a new functional beverage based on a dealcoholized red wine matrix supplemented by a pomegranate extract. The potential bioactive compounds in the pomegranate extract, punicalagin A and B and ellagic acid, were analyzed during the downstream process in order to evaluate the functional dose in the final beverage. The addition of pomegranate extract to the dealcoholized red wine resulted in a product with more intense yeast odor, acidity, yeast flavor, and astringency and with a less intense berry flavor. Consumer acceptance of the product was also investigated and the results revealed the existence of a niche of consumers willing to consume dealcoholized wine enriched with pomegranate extract. After tasting, 50% and 40% of those consumers initially interested by this product concept declared to be interested to purchase the control sample and the functional beverage, respectively. The daily consumption of two servings of 250 mL of this new pomegranate-enriched dealcoholized wine provides 82 mg of total ellagitannins, corresponding to the sum of punicalagin A and B and ellagic acid.

LDL cholesterol-lowering effects of grape extract used as a dietary supplement on healthy volunteers.

The aim of this study was to evaluate the effects of Eminol®, the polyphenol-rich grape extract supplement (700 mg), on cardiovascular risk and oxidant stress indicators in a sample of volunteers. A randomized, double-blind, placebo-controlled clinical trial was performed over 56 days and included 60 volunteers. Thirty volunteers took 700 mg of the grape extract, Eminol® (E), and 30 took the placebo (P). On comparison of the results, a decrease in total cholesterol (E: 213.77 ± 4.1 mg/dl and P: 245.57 ± 4.1 mg/dl; p = 0.01) and LDL cholesterol (E: 142.17 ± 3.1 mg/dl and P: 165.13 ± 3.1 mg/dl; p = 0.02) levels as well as an increase in antioxidant capacity (E: 65.63 ± 5.8 µmol TE/mg and P: 57.80 ± 7.7 µmol TE/mg; p < 0.01) and vitamin E (E: 11.46 ± 0.5 µg/ml and P: 9.06 ± 0.5 µg/ml; p = 0.018) was observed. This result indicates that the grape extract Eminol® modulated the lipid profile in terms of cardiovascular risk indicators, lowering total blood cholesterol and LDL cholesterol levels.