Postharvest Fruit Weight Loss, Pericarp Water Loss and their Relation to Pericarp Browning of Longan

摘要

Longan (Dimocarpus longan Lour.) fruit are very susceptible to water loss, and postharvest pericarp browning is the most important factors affecting storage life and quality of longan fruit. Fruit weight loss, pericarp water loss and their relation to pericarp browning of longan （Dimocarpus longan Lour. cv. Fuyan） under the storage conditions with (10±1)°Cand 50% relative humidity, and effects of polyethylene (PE) film bag (0.015mm thick) sealed packaging and storage temperatures (4°C or 20°C.) on moisture loss and pericarp browning of longan fruit were investigated in this experiment. The results indicated that longan fruit stored for 1, 2, or 6 days at 10°C and 50% RH lost 5.84%, 10.37% and 23.98% fresh weight, respectively, and water loss from the pericarp was 13.59%, 26.40% and 42.78 %, respectively, but there was minimal weight loss of the aril and seed part. Hence, selective dehydration of the pericarp occurred with little movement of water between the aril and the pericarp, and water loss of fruit was mainly from the pericarp rather than the aril. Both weight loss from fruit and water loss from pericarp were positively correlated with pericarp browning index significantly (P<0.01). Storage in plastic films bags and low temperatures is effective in reducing moisture loss and desiccation-induced browning. 'Fuyan' fruit packed in PE film bags and held at 20°C lost 2.87% of their weight after 15 days, while fruit held at 4°C only lost 2.01% after 30 days. Storage at 4°C also retarded pericarp browning and extended storage life of fruit.