Chitosan coating modulates cell wall degrading enzymes and preserved postharvest quality in cold-stored pear fruit

The effectiveness of chitosan coating to delay the postharvest losses and preserving fruit quality in pear (Pyrus pyrifolia Burm.) cultivar “Patharnakh”, as well as its effect on enzymatic activities involved in the fruit softening were evaluated during long term storage. Pear fruits were coated with 0.5%, 1.0%, 2.0% chitosan (CH) emulsions and stored at low temperature storage conditions (0–1 °C and 90–95% RH) for 70 days. At each sampling date, fruits were analysed for various physico-chemical and enzymatic changes. As compared to control, the CH 2.0% coatings lowered the weight loss (∼18%), retained higher firmness (∼16%), suppressed respiration rate (∼43%) and sustained soluble solids content (∼12%), titratable acidity (∼7%), total phenol content (∼32%) up to end of storage and thus conserved most of the fruit quality parameters for a longer period. Additionally, the chitosan coated fruit exhibited lower spoilage, and lessened the activities of fruit softening enzymes including like pectin methylesterase, polygalacturonase, and cellulase. These coatings restricted PPO activity, preventing browning and extending the storage life of pear fruit. The efficacy of chitosan coating on regulation of softening enzyme activities, along with delaying in ripening related changes can be exploited in other fruits.