Abstract
‘Schiava’ grapes contain peonidin-3-O-glucoside as main anthocyanin, which is associated to colour instability in the wines. A primary objective of this study was to test a potential strategy (grape freezing) to increase the pigments’ extraction from these grapes, and/or the colour stability in wine. Evaluated variables were: (1) application of grapes freezing or not; (2) fermentation with or without fermentative maceration; (3) fermentation by inoculum with Saccharomyces cerevisiae, or co-inoculum with S. cerevisiae and Oenococcus oeni. Potential interactions between grape freezing and malolactic fermentation were also evaluated. Without fermentative maceration, wines from frozen grapes presented “light/pink”, “pink/salmon” (visual), “nutty/almond”, “tropical/banana” (aroma) attributes. Although grape freezing allowed higher initial contents of peonidin-3-O-glucoside in must, no significant differences were found in the wines after storage. Colorimetric parameters were still positively impacted by grape freezing: The profile of free anthocyanins could not alone accurately reflect the colour of the wines, as other relevant factors were significant.