Abstract

Variations in total polyphenols and in some esterified and free phenolic acids, caused by flor formation in the ageing process of “Vernaccia di Oristano”, were studied using HPLC analysis. The experiments showed that “Vernaccia di Oristano” has a much higher quantity of total polyphenols than other white wines and that this value decreases when the wine is inoculated with flor yeasts. It was also noted that the quantity of free cinnamic acids and of their tartaric esters is very low and that contact between wine and yeast causes an increase in the former and a decrease in the latter. The greatest interactions were recorded between 1043 and AMBRA strains, and trans-p-feruloyl tartaric acid and trans-2-S-glutathionyl caffeoyl tartaric acid (GRP). With inoculated samples the variations observed in total polyphenols corresponds to a sharp decrease of absorbency at 420 nm. The decreases in Optical Density and total polyphenols do not, however, appear to be correlated.

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