采收前后梨枣果实转红与果皮活性氧代谢比较

Comparison of Turn Red and Peel Jujube Active Oxygen Metabolism and its Relation of Pear-jujube Fruit in and out of the Tree

以梨枣为试材,研究枣果树上和采后转红与果皮酚类物质、褐变酶及活性氧代谢的关系,结果表明树上枣果果皮活性氧代谢与采后枣果不同。树上枣果果皮SOD、CAT活性呈上升趋势,O-2产生速率、H2O2含量变化较为平缓。采后枣果果皮SOD、CAT活性均呈下降趋势,O-2生成速率、H2O2含量均呈上升趋势,采后枣果果皮SOD、CAT活性与褐变度均呈显著负相关,O-2生成速率、H2O2含量与褐变度呈显著正相关,果皮SOD活性与O-2生成速率、CAT活性与H2O2含量均呈显著负相关,说明抗氧化酶对活性氧的清除能力降低,活性氧积累,MDA含量增大,果皮膜脂过氧化作用加强。综上可知,树上枣果转红过程中活性氧代谢平衡,而采后枣果果皮活性氧代谢失调,膜脂过氧化作用加强,褐变发生。

This paper presents the research of the relationship among total phenol,browning enzymes and active oxygen metabolism during on the tree and postharvest turn red period based on pear- jujube tree. The results showed that active oxygen metabolism of the jujube peel in tree was different from postharvest jujube. In tree jujube peel＇s SOD and CAT activity show a trend of rising,and the O-2production speed and H2O2 content change were gentle. Postharvest jujube peel＇s SOD and CAT activity declined. The O-2production speed and H2O2 content raised; Postharvest jujube peel＇s SOD and CAT activity and browning degree showed evident negative correlation; the O-2production speed and H2O2 content and browning degree showed significant positive correlation.The peel＇s SOD activity and O-2production speed,CAT activity and the H2O2 content showed evident negative correlation,it suggests that the ability of antioxidase eliminating the active oxygen reduced,caused the active oxygen accumulation,the MDA content increased,it suggested that epithelium fat peroxidation function of the jujube peel strengthened. In brief,the active oxygen metabolic during the turning red process was in balance,but postharvest jujube peel＇s active oxygen metabolism was out of balance,the membrane fat peroxidation function strengthens and browning happened.