包装对龙眼果实贮藏期间果皮失水褐变和细胞超微结构的影响

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

研究了(10±1)℃和50%相对湿度贮藏条件下无包装和0.015 mm厚的聚乙烯薄膜袋密封包装的"福眼"龙眼果实果皮失水、果皮褐变和细胞超微结构变化。结果表明,无包装的龙眼果实采后极易失水导致果皮迅速褐变,且褐变随贮藏时间的延长和果皮失水率的增加而升高,果皮褐变指数与果皮失水率呈极显著正相关(P<0.01)。在龙眼果皮失水褐变过程中,果皮细胞的细胞器和膜系统的完整性受到严重的破坏。而聚乙烯薄膜袋密封包装则显著减少了果皮失水和抑制果皮褐变,并保持较好的果皮细胞的细胞器和膜系统的完整性。据此认为,聚乙烯薄膜袋密封包装抑制龙眼果实失水果皮褐变与其维持细胞器和细胞膜的完整性有联系。

Water loss of pericarp, desiccation-induced pericarp browning and changes in cellular uhrastructure 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.