Effects of pre-fermentation enzyme maceration on extraction and colour stability in Pinot Noir wine

Effects of pre-fermentation enzyme maceration on anthocyanins, phenolics, c olour and colour parameters were investigated in Pinot Noir (Vitis vinifera L.) wines made from musts that were macerated for 12 hours at 20 degreesC with a commercial enzyme preparation, Rohapect VR-C (Rohm, Darmstadt, Germa ny), with and without additions of SO2. Anthocyanins and phenolics were det ermined by spectrophotometric and HPLC methods. Standard triplicate microvi nifications were conducted in glass vessels. Extraction of anthocyanins was not increased by enzyme treatment. However, wines produced by enzyme macer ation had increased visible colour intensity, colour density and polymeric pigment formation. By the end of fermentation, enzyme-treated wines had mor e polymeric pigment, and less monomeric anthocyanins than non-enzyme-treate d wines. The wines were bottled, stored at 12 degreesC and sampled at three , six, eight and 18 months after bottling. Over 18 months, differences betw een the treatments were maintained. The promotion of the formation of polym eric pigments in enzyme-treated wines continued after the wines were bottle d, and the greater content of polymeric pigment led to greater colour densi ty in the enzyme-treated wines. The promotion of polymeric pigment formatio n in wines by macerating enzyme treatment of the must may be due to the bre akdown of protective polysaccharide-protein colloids by hemicellulase and p rotease activities in the enzyme preparation.