Abstract: ‘Marselan’ (Vitis vinifera L.) grape berries were used to investigate the effect of flash vacuum expansion on monomeric phenolics and CIELab color parameters during wine fermentation and maturation. The results showed that compared to the control group (maceration-fermentation), flash vacuum expansion increased the concentration of most monomeric anthocyanins during fermentation, but was not favorable to maintain the concentration of monomeric anthocyanins during aging. Flash vacuum expansion increased the concentrations of non-anthocyanin monomeric phenolics such as quercetin-3-O-glucoside, catechins, trans-resveratrol, and resveratro-3-O-β-D-glucoside, but decreased the concentrations of quercetin, myricetin, phenolic acids, cis-resveratrol, and piceatannol during wine fermentation and maturation. Flash vacuum expansion reduced the color parameters brightness (L*), yellowness-blueness (b*) and hue angle (hab) values, but significantly increased redness-greenness (a*) and chroma (Cab*) vales, which made the wine’s color redder, darker and more stable. There was a significant color difference between the two groups. In conclusion, flash vacuum expansion can increase the total amount of monomeric phenolics and the color stability of ‘Marselan’ wine.

Key words: flash vacuum expansion; ‘Marselan’ wine; monomeric phenolics; color parameters