Post-harvest calcium chloride treatments influence fruit firmness, cell wall components and cell wall hydrolyzing enzymes of Ber (Ziziphus mauritiana Lamk.) fruits during storage

摘要

Ber fruits of two varieties having variable shelf lives viz. Umran (8-9 days) and Kaithali (4-5 days) given post-harvest treatments of calcium chloride (1% and 2%) were analyzed for various cell wall components, cell wall hydrolyzing enzymes and fruit firmness at 2 days interval until complete decay. There was a continuous decrease in cellulose, hemicellulose and pectin contents during storage in both the varieties with more reduction in Kaithali, a variety having short shelf-life. The decline in cell wall components was accompanied by parallel increase in activities of cellulase, polygalacturonase (PG) and pectin methylesterase (PME). Post-harvest treatment of Ber fruits with calcium chloride resulted in significantly lowering of activities of cellulase (20-22%), PG (23-29%) and PME (25-28%) thereby retaining higher cell wall components viz. cellulose (9-11%), hemicellulose (7-8%) and pectin (12-13%) as compared to their respective control in both the varieties. The delay in cell wall hydrolysis, as mediated by calcium chloride corresponded to the higher retention of fruit firmness.