Transformation of Anthocyanins During Preparation of Rose Wine by Following a Pre-fermentative Cold Maceration Process

Abstract

Castelao is a Portuguese native grape variety commonly used in the south of the country to produce white, rose and red wines. This work reports a study on the transformation of anthocyanins of Castelao grape variety during the preparation of a rose wine. The grapes were collect at Quinta dos Vales (Estombar – Lagoa, Algarve) vineyards. The rose wine was prepared at Quinta dos Vales by following a pre-fermentative maceration process at 4 °C during 5 h. The anthocyanins were analysed in grape’s skin and in prepared wine by LC-DAD-MS. The total phenol contents of skin extracts and wine were made by following the Folin-Ciocalteu method. The quantification of individual anthocyanins was performed by HPLC-DAD using traces obtained at 520 nm and malvidin-3-O-glycoside as standard. The anthocyanins identified in the grape skin were: delphinidin-3-O-glycoside, petunidin-3-O-glycoside, peonidin-3-O-glycoside, malvidin-3-O-glycoside, malvidin-3-O-acetylglycoside and malvidin-3-O-coumarinoglycoside. The most abundant anthocyanin in the skin is malvidin-3-O-glycoside, (1.1 mg/g of dry skin). Its content relatively decreases during wine preparation. The major anthocyanin in wine is malvidin-3-O-coumaroylglucoside (12.7 mg/L). Although the same anthocyanins were identified in grapes and wine, the results show a significant effect of the maceration and fermentation processes on the anthocyanin profiles.