Test of four generations of Saccharomyces cerevisiae concerning their effect on antioxidant phenolic compounds in wine.

Red wine quality is primarily dependent on its phenolic content that confers colour, flavour, healthy properties, and natural antioxidant activity. The aim of this research was to study the behaviour of 70 different Saccharomyces cerevisiae strains concerning their effect on wine content in antioxidant phenolic compounds. This research was carried out using the control strain Zymaflore F15 (Laffort Oenologie, France), eight Italian wild types, 12 derived spore clones, 15 hybrids obtained crossing the derived spore clones, and 34 spore clones derived from the hybrids. Black grapes of the Cabernet variety were destemmed, crushed, cold soaked at 4 °C for 3 days and punched down twice per day. The must obtained after pressing (27°Brix) was inoculated in triplicate at 5% with precultures of the 70 yeast strains and incubated at 25 °C. At the end of the winemaking the wines, analysed by HPLC for their antioxidant phenolic content, showed highly significant differences, due exclusively to the wine starter used. In details, catechin content ranged from 0 to 79.53 mg/l (mean 31.67), epicatechin content ranged from 0 to 70.51 mg/l (mean 19.24), vanillic acid content ranged from 3.10 to 12.71 mg/l (mean 8.72), gallic acid content ranged from 2.54 to 6.77 mg/l (mean 4.82), rutin content ranged from 0 to 11.77 mg/l (mean 3.46), quercetin content ranged from 0 to 2.09 mg/l (mean 1.62), caffeic acid content ranged from 0 to 10.63 mg/l (mean 1.28), trans-resveratrol content ranged from 0 to 0.85 mg/l (mean 0.27). Data validate the main role that wine yeast selection plays to enhance red wine content in antioxidant phenolic compounds.