Dynamics of biochemicals of Punjab MACS Purple and H-144 from veraison to maturity under Punjab conditions

Grape [cv. Punjab MACS Purple (PP) and H-144] berries were analysed at different maturity stages for°Brix, anthocyanins, total phenols, ascorbic acid, pH, titratable acidity, tartaric acid, malic acid, total sugars, reducing sugars, glucose and fructose contents to select optimum harvesting stage for quality wine production. An increase in the berry size during the maturation period increased°Brix to 18.0 & 16.4°B and sugars to 17.6 and 15.6% in PP and H-144, respectively. The final glucose and fructose contents were 82.1, 90.2 and 74.2, 77.8 g/l that lead to glucose/fructose ratio of 0.91 and 0.96 in PP and H-144, respectively, while, malic and tartaric acids decreased to 4.0, 4.4 and 3.7, 4.5 g/l in fully ripened berries of PP and H-144, respectively. Total phenolics, anthocyanins and ascorbic acid contents were found to increase during the maturation period. Thus, the study defined 19–20 and 12–15 days of veraison in PP and H-144, respectively for optimum maturity under Punjab agro-climatic conditions.