Evolution Of Phenolic Compounds During The Red Grapes Fermentation In The Presence Of Trace Metals

Polyphenols are second metabolites originating from vegetable sources. They are of great importance due to their capacities of capturing free radicals which are known to be responsible for damaging cells and tissues. In grapes and subsequently in grape must, among other constituents, polyphenols, originating from grape skin, are found in good amount, especially in the red varieties.In this article, the attention was focused on the influence of some added metals on the polyphenols content in grape must, during must fermentation process. The influence was studied through spectroscopic techniques UV-VIS and 1H-NMR. The results showed that metals, added in a pre-fermentative stage of the grape must determine a more pronounced colour and a higher number of polyphenols in the final product: wine.