Effect of low-temperature hardening on postharvest storage of Litchi fruit

Litchi (Litchi chinensis Sonn. cv. Huaizhi) fruit were placed at 5 degrees C for low-temperature hardening treatments for 5 days and then stored at 1 degrees C for 40 days to investigate the possibility of extending Litchi fruit storage life and its physiological changes. A 0.03 mm thick polyethylene film and TBZ (0.1% Thiabendazole) were used in packaging and to control decay of the fruit during storage. Respiration rate, cell membrane permeability, browning grades, and peroxides in litchi peel were measured. Organic acid and ascorbic acid levels and the shelf life of the fruit were also investigated. The results showed that during storage, a low-temperature hardening treatment can slow down respiratory rates during the later period of storage, changes in cell membrane permeability, browning grades, and peroxides in peel. It can also slow down the decrease in organic acid and ascorbic acid levels, and extend the shelf life of litchi fruits after removal from cold storage. These results indicated the capability of acclimatizing of litchi fruit was increased after low-temperature hardening treatment, accounting for the extension of storage and shelf life of the litchi fruit. However, further study should be needed to ensure whether 5 degrees C is the optimal temperature for low-temperature hardening.