Ripening associated biochemical changes with relation to jelly seed formation in mango cv. Dashehari, Langra and Chausa.

Abstract

Mango fruit during ripening shows considerable changes in physiological and biochemical processes. Ripening associated biochemical changes viz., physiological weight loss (PLW), chlorophyll content, respiration rate, ethylene level, pectin methyl esterase (PME) and polygalacturonase (PG), catalase and peroxidase activities and their relation with softening of tissue in Chausa, Langra and Dashehari mangoes were studied at different period of their storage. Wide variations with superiority in Chausa in these attributes were recorded. The maximum PLW (24.36%) was recorded in Dashehari and minimum (13.19%) in Chausa on 9 day after storage. Maximum decrease in all type of chlorophyll was found in Dashehari at 9 day after storage. The rate of respiration and ethylene began to increase from 0 day to 7 day in all cultivars and rate of respiration was considerably low on 9 day of storage in case of Chausa, however Dashehari and Langra on 9 day after storage showed the decrease level in both the attributes. The pectin methyl esterase (PME) activity increased initially up to 4 days (895 unit / min / g FW) and decreased slowly on 7 day (600 unit / min / g FW). On the other hand the activity of PME was decreased sharply (120 unit / min / g FW) on 9 day of fruit storage in Dashehari, Chausa and Langra. Contrary to the PME activity, the polygalacturonase (PG) activity was increased consistently with increasing the storage period up to 7 day in all the cultivars, thereafter, its activity gradually declined in Chausa and Dashehari. However, cultivar Langra maintained its activity up to 9 day of storage (400 mg glucose released / g FW). Thus, maximum activity of PME and PG in Dashehari cultivar at early stage of ripening may be associated with the incidence of softening in Dashehari.