Effects of Skin Fermentation Time on the Phenols, Anthocyanins, Ellagic Acid Sediment, and Sensory Characteristics of a RedVitis rotundifoliaWine

Abstract

Noble muscadine grapes (<i>Vitis rotundifolia</i>) were harvested at two stages of maturity (optimum, based on full color and flavor development and pH below 3.3, and 14 days later) and either pressed immediately for a blush wine or fermented on the skins for two, four, or six days. Red wines from more mature grapes had greater color intensity and higher levels of anthocyanins, total phenols, and non-polymeric phenols. Wines from the more mature grapes had higher levels of the 3,5-diglucosides of peonidin (Pn) and malvidin (Mv), and lower levels of delphinidin (Dp), cyanidin (Cy), and petunidin (Pt). Maximum color and anthocyanin extraction occurred within four days of skin fermentation with the optimum maturity fruit, but continued through day six with later maturity fruit. However, wines fermented on the skins for four or six days had less muscadine aroma intensity and were more astringent. Skin fermentation time had little effect on the distribution of anthocyanins, although the immediate press wines had lower levels of Dp and Mv and higher levels of Cy and Pn. Total, non-polymeric and polymeric phenol levels increased with increasing skin fermentation time, but the polymeric phenol levels and anthocyanin polymerization were generally low in all wines.