BIOCHEMISTRY OF UNEVEN RIPENING IN GULABI GRAPE

Physico-chemical changes, organic acids content and activities of enzy mes related to softening, glycolytic, gluconeogenic and organic acids metabolism were studied from 70 to 100 days after anthesis in ripening of berries of Gulabi grape. Uneven ripening was observed in 70 day ol d clusters. The disorder affected 22.76 and 32.38% of berries in bunch es harvested at 90 and 100 days, respectively. Unripe berries had less dry matter, sugars, skin anthocyanins and more seed, fresh weight and acidity compared to ripe berries. Green berries had more malic and le ss tartaric acid, while brown berries had less malic acid and black be rries contained more tartaric acid. Green berries contained more polyg alacturonase, cellulase, hexokinase, glucose 6-phosphatase, phosphoeno lpyruvate carboxylase, pyruvate decarboxylase and polyphenol oxidase a ctivities than ripe fruit. Brown berries contained the highest phospho fructokinase, malate and glutamate dehydrogenase activities, and black berries had the highest activities of pectinesterase, fructose 1,6-bi sphosphatase and malic enzyme. The role of dry matter, malic acid, pec tinesterase and certain enzymes of gluconeogenic and organic acids met abolism in uneven ripening is discussed.