Pre-drying and submerged cap winemaking: Effects on polyphenolic compounds and sensory descriptors. Part II: BRS Carmem and Bordô ( Vitis labrusca L.)

Phenolic Composition of Brazilian BRS Carmem (Muscat Belly A × BRS Rúbea) Grapes: Evaluation of Their Potential Use as Bioingredients

The BRS Carmem grape was developed as an alternative for processing juices and wines. This study aimed to determine the phenolic compounds (PC) in the edible parts of this grape from two harvests-one harvested at ideal maturation time and another when the grapes were still immature-using HPLC-DAD-ESI-MS/MS. Student's t-test was used (α = 0.05) to evaluate differences in the PC content between the edible parts and between the harvests. Both skins showed a predominance of flavonols, anthocyanins, hydroxycinnamic acids derivatives (HCAD) and stilbenes, with higher concentrations for harvest 1 than harvest 2. For both harvests (harvest 1 and harvest 2), the HCAD (mg of caftaric acid•kg fruit^-1) was higher in whole grapes (383.98 and 67.09) than in their skins (173.95 and 21.74), with a predominance of trans-caffeic acid for all samples; the flavan-3-ols and proanthocyanidins (mg of (+)-catechin•kg fruit^-1) presented higher concentrations in the seeds (flavan-3-ols: 203.20 and 182.71, proanthocyanidins: 453.57 and 299.86) than in the skins (flavan-3-ols: 1.90 and 4.56, proanthocyanidins: 37.58 and 98.92); the stilbenes concentration (µg 3-glc-resveratrol•kg fruit^-1) was higher for the seeds from harvest 2 (896.25) than those from harvest 1 (48.67). BRS Carmem grapes contain a phenolic composition complex, and still have a relevant concentration of flavonols, anthocyanins and stilbenes, even when immature.

Antioxidant/Pro-Oxidant Actions of Polyphenols From Grapevine and Wine By-Products-Base for Complementary Therapy in Ischemic Heart Diseases

Grape pomace and grape seeds, by-products of the wine industry, and grapevine cane resulting from grapevine pruning are cheap matrices containing important amounts of polyphenols. While there is a continuous need of introducing new ways of these by-products valorization, we propose their use as a source of bioactive polyphenols for complementary therapy in ischemic heart diseases. As oxidative stress plays an important role in these diseases, by their antioxidant/pro-oxidant properties, these compounds, mainly flavan-3-ols, procyanidins, and resveratrol may counteract the damage of the oxidative stress. For instance, to some extent, the grape seed extract, considered as an antioxidant nutritive supplement, may have pro-oxidant activity as well, depending on dose, duration of administration, and other dietary components. In vitro studies confirm that the antioxidant activity of this extract might be mediated by pro-oxidant o-quinones and oxidation products of the polyphenols from grape and winery byproducts, indicating that quinones, as oxidation products, are involved in the modulation of the antioxidant/pro-oxidant balance at the cellular level in the case of catechin-type compounds, in the absence or presence of oxidative stress inducers. In vivo, studies indicate that a grape pomace-rich diet results in a significant increase of the total antioxidant status in the plasma, liver, spleen, and kidneys. Also, the administration of grape pomace shows antioxidant activity with positive effects on health. In this context, the present review aims to present the most recent research focused on the antioxidant/pro-oxidant actions of the bioactive polyphenols from grapevine and wine byproducts, in conditions of ischemic heart diseases as assessed in vitro or in vivo.

Viscosity of liquid and semisolid materials: Establishing correlations between instrumental analyses and sensory characteristics

Considering the importance of texture for food products, we aimed to evaluate viscosity of different liquid and semisolid materials through instrumental analyses (rheometer and texture analyzer), as well sensory descriptive analysis, and establishing correlations between all these analyses. Eight materials were used: water, strawberry yogurt, condensed milk, honey, UHT cream, creamy dairy dessert, petit suisse strawberry flavor (a traditional French cheese from Normandy region, and sold as an infant product), and dulce de leche (obtained through cooking of a can of condensed milk, during 15 min under pressure, resulting in a brownish color product and more consistent than condensed milk). All materials were submitted to rheological analysis, analysis on texture analyzer, and descriptive sensory analysis. All techniques of measurement discriminated the texture of samples. The visual viscosity, defined as a sensory attribute evaluated by visual observation, was negatively correlated to apparent viscosity measured through rheological analysis with shear rate at 10 s^-1 . Oral viscosity and body (both defined as sensory attributes evaluated by oral perception) were positively correlated with areas from graphs obtained in the texture analyzer, and with apparent viscosity measured through rheological analysis at shear rate of 10 s^-1 , although positive strong correlation was also found between body and apparent viscosity at higher shear rates (50 and 100 s^-1 ). The strong correlations enable application of these instrumental tests as indicators of the sensory texture of liquid and semisolid materials. PRACTICAL APPLICATIONS: Texture has a minor importance to liquid and semisolid materials in comparison to meat and crunchy products. However, the relevance of texture to these kinds of products has growing up recently. Therefore, measuring and understanding viscosity of liquid and semisolid materials, using different ways of evaluation, brings relevant information to the area. Moreover, establishing correlations between instrumental and sensory analyses may indicate which instrumental analysis and which analysis condition would be more adequate to correlate with sensory perception of texture, allowing a convergence for future studies and for discussion of results.