Effects of pH, temperature and SO2 on the formation of pyranoanthocyanins during red wine fermentation with two species of Saccharomyces.

The formation of vitisins A and B, p-coumaroyl and acetyl derivatives during the fermentation of red wine with two species of Saccharomyces was examined. One species, Saccharomyces cerevisiae strain 7VA was selected for its high production of acetaldehyde and pyruvic acid (7VA). The other (control) species, Saccharomyces uvarum strain S6U is used commercially for wine production. The final vitisins A and B concentrations produced with S. cerevisiae were, respectively, twice and three times that produced with S. uvarum. Models for the formation and accumulation of these vitisins are proposed. This is the first report that the formation of a vinylphenolic derivative of anthocyanin, malvidin-3-O-glucoside-4-vinylguaiacol, can be favored by fermentation with certain yeasts, possibly those with cinnamoyl decarboxylase activity. The effect of SO2, pH and temperature on the formation of pyranoanthocyanins during fermentation with S. cerevisiae and S. uvarum was also analyzed using High Pressure Liquid Chromatography (HPLC)/Photodiode Array Detection. The identification of these compounds was confirmed using HPLC/Electrospray Ionization-Mass Spectrometry.