Differential interaction of seed polyphenols from grapes collected at different maturity stages with the protein fraction of saliva

Abstract

Grape seed and skin proanthocyanidins undergo significant changes during grape maturation. Those changes have been associated with a decreased astringency of grapes collected at later maturation stages. We have now compared the ability of proanthocyanidin-rich extracts from Carme´ne`re grape seeds collected at two stages of berry development (veraison vs. harvest) both to interact with salivary proteins and to produce astringency. Interaction of proanthocyanidins with the salivary protein was assessed by analysing the concentration-dependent effect of seed extracts both on inducing salivary protein precipitation and on restricting diffusion of the salivary protein on cellulose membranes. Seed extracts from grapes collected at veraison compared with those of grapes collected at harvest displayed a higher ability both to interact with the salivary protein fraction and to produce astringency. As a whole, our observations show that astringency is closely dependent on the magnitude of the interactions between proanthocyanidins and the salivary protein fraction.

Phenolic composition and antioxidant capacity of pomaces from four grape varieties (Vitis vinifera L.)

“…Finally, in this study we observed that C and EC were the most abundant flavonoid polyphenols in pomaces from both white and red grape varieties, which is consistent with previous observations in V. vinifera L. grape seeds and skins . It is important to recall that in this study white grape pomaces showed higher concentrations of both compounds compared with red grape pomaces.…”

“…Interestingly, both SB and CA showed GA concentrations twice as high as those found in CH and CS respectively. This trend may be highly relevant, since GA has been linked to important sensory properties such as bitterness and astringency . In this regard, we have recently described that GA displays growth‐inhibitory effects on Helicobacter pylori , a common pathogenic gut bacterium …”

“…This trend may be highly relevant, since GA has been linked to important sensory properties such as bitterness and astringency. 5,9 In this regard, we have recently described that GA displays growth-inhibitory effects on Helicobacter pylori, a common pathogenic gut bacterium. 35 Finally, in this study we observed that C and EC were the most abundant flavonoid polyphenols in pomaces from both white and red grape varieties, which is consistent with previous observations in V. vinifera L. grape seeds and skins.…”

“…In Vitis vinifera L. grapes, the most abundant polyphenols can be categorized according to their chemical structures into flavonoids and non‐flavonoids. Flavonoid compounds are predominantly found in the skins, seeds and stems, whereas non‐flavonoid compounds are most abundant in the berry pulp …”

Modelling phenolic and technological maturities of grapes by means of the multivariate relation between organoleptic and physicochemical properties

“…[1,2] as well as its interactions with the protein fraction of saliva [3]. Many 49 works have been devoted to quantify the effect of maturity on several physicochemical 50 parameters, for example, to distinguish between grape varieties [4], or the importance of the 51 extraction methodology when monitoring seed maturity for prediction of the seed tannins in 52 wine [5].…”