Functional Tannins in Grape Pomace Flours of Feteasca Neagra and Italian Riesling

Abstract

The aim of this study was to analyze the content of functional tannins in grape pomace skin, seed, and mixed flour, from Feteasca Neagra and Italian Riesling varieties. Results showed that all compounds were present in the highest concentration in grape pomace seed flours and the lowest in skin flours. The concentration of total tannins and total flavan-3-ol monomers in all flour samples ranged from 37.34 to 72.28 mg epicatechin/g dry weight and 0.57 to 3.13 mg/g dry weight, respectively. Among monomers, (+)-catechin was found in the highest concentration, except in Italian Riesling seed flours, where (-)-epicatechin was predominant. The mDP of proanthocyanidins in seed flour (7.15 to 8.07) is lower than that of skin flours (10.83 to 18.43) while the opposite was observed for %G. As a result, all Feteasca Neagra and Italian Riesling grape pomace flours, especially seed flour, could be used as sources of functional tannins in alimentary or pharmaceutical industry.

Characterization and Classification of Romanian Wines by Origin A chemometric approach based on some metals and phenolic composition

“…Wines were also classified based on the phenolic compounds [17,18] which are significant secondary metabolites of plants concentrated in the husks, seeds and pulp of beans grape and wine extracts [2,19] contributing to the formation of specific characteristics of wine such as colour, aroma, mouth-feel (astringency) and flavour, the most abundant and functional polyphenols being flavan-3-ol monomers, -catechin and (-)-epicatechin. [20]. These compounds are responsible for different wine types [21].…”

“…The structure of these compounds differs depending on the fraction of the grape, through their mean degree of polymerization. [20].…”