Effects of chitosan coating on enzymatic browning and decay during postharvest storage of litchi (Litchi chinensis Sonn.) fruit

Litchi (Litchi chinensis Sonn, cv. Huaizhi) fruit were treated with aqueous solutions of 1.0 or 2.0% chitosan coating 1 h after dipping in 0.1% thiabendazole (TBZ), and then stored at 4 degrees C and 90% relative humidity (RH). Changes in browning, anthocyanins, flavonoids, total phenolic contents, polyphenol oxidase (PPO) and peroxidase (POD) activities, and weight loss were measured. The effects of chitosan coating on decay control were also evaluated. The application of chitosan coating delayed changes in contents of anthocyanin, flavonoid, total phenolics, delayed the increase in PPO activity, reduced weight loss, and partially inhibited the increase in POD activity. All these changes corresponded to changes in browning. The application of chitosan coating partially inhibited decay of fruit during storage. However, increasing the concentration of chitosan coating did not significantly increase the beneficial effects of chitosan on browning and decay of the fruit. (C) 1997 Elsevier Science B.V.