Effects of packaging on desiccation-induced browning and cellular ultrastructure of pericarp of longan fruits during storage

Water loss of pericarp, desiccation-induced pericarp browning and changes in cellular ultrastructure of pericarp of "Fuyan" longan(Dimocarpus longan Lour. cv. Fuyan) fruits were investigated. Fruits were packaged in sealed polyethylene film bags and the fruits without packaging as a control. Both control and treatment fruits were stored at (10±1)℃ and 50% relative humidity. The results indicate that control fruits are very susceptible to water loss, and water loss results in rapid pericarp browning. Development of pericarp browning increases higher with rate of water loss from pericarp and storage time(from zero to six days) increasing. Water loss from pericarp is positively correlated with pericarp browning index significantly(P<0.01). Serious breakdown of organelle and integrity of cellular membrane structure of longan pericarp were observed during desiccation-induced pericarp browning. Longan fruits which sealed polyethylene film bags are effective in reducing moisture loss and desiccation-induced pericarp browning, and delay breakdown of organelle and maintained integrity of cellular membrane structure of pericarp. It is suggested that partial protection from breakdown of organelle and maintenance of cellular membrane integrity of longan fruits by sealing polyethylene film bags can reduce desiccation-induced pericarp browning.