Phenolic and Chromatic Properties of Beibinghong Red Ice Wine during and after Vinification

The phenolic and chromatic characteristics of a special red ice wine made from a Vitis amurensis x V. vinifera hybrid cultivar Beibinghong were studied. Results from two different vintages (2013 and 2014) showed that during vinification, the phenolic acid content increased, while the level of flavonoids (flavonols, flavan-3-ols, and anthocyanins) reduced by a variable extent. The color intensity and red % decreased together with a decrease in anthocyanin content. This was accompanied by an increase in hue as well as yellow %. The final phenolic content was found to be between 119.54 and 180.93 mg/L, with anthocyanins as the predominant phenolic group (92.06%-93.03%), of which 3,5-O-diglucosidic anthocyanins made up 53.55%-79.04%. Phenolic acids were the primary non-anthocyanin phenolics at about 6.64%-7.5%. The phenolic contents and color parameters of Beibinghong dry red wine and several V. vinifera dry red wines of superior color quality were also used in an attempt to clarify the relationship between phenolics and color in the Beibinghong red ice wine. By using Pearson correlation analysis and principal component analysis (PCA), it was found that 3,5-O-diglucosidic anthocyanins and protocatechuic acid were the only characteristic phenolics that differentiated Beibinghong wines from the other selected red wines from more traditional varieties. They were also the main phenolics to be positively correlated with the hue and yellow % of the wine at the early stages leading into maturation. Their presence might, therefore, explain the relatively high hue and yellow % of Beibinghong ice wine.