低温对荔枝果肉膜脂过氧化和保护酶活性的影响

Effect of Low-temperature Storage on Membrane Lipid Peroxidation and Activities of Cell Defense Enzyme in Litchi Pulp

对‘白蜡’荔枝果肉在3℃和-1℃下的贮藏效果及果肉膜脂过氧化和保护酶活性进行了研究。结果表明,去果皮的荔枝果肉在3℃下贮藏40 d,-1℃下保鲜50 d,不表现冷害症状。低温下果肉的细胞膜透性、丙二醛(MDA)含量逐渐增加。冷藏30 d,-1℃与3℃果肉之间的膜透性、MDA含量没有显著差异,但30 d后,-1℃处理明显延缓了果肉膜透性和MDA含量的增加。在3℃下贮藏果肉的超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(ASA-POD)和过氧化氢酶(CAT)活性在20 d、过氧化物酶(POD)活性在30 d时分别到达高峰值。-1℃延缓了这些保护酶活性的升高并降低了峰值。

Pulp of litchi (cv. Baila) was used to investigate the changes of membrane lipid peroxidation and the activities of cell protective enzymes during storage at low temperatures. The results showed that the litchi pulp could be maintained well for 40 days at 3℃ or 50 days at -1℃ without symptoms of chilling injury. The cellmembrane electrolyte leakage and malondialdehyde (MDA) content of the pulp stored at 3℃ or -1℃ increasedgradually with time of storage, and showed no marked difference between the two temperature treatments within 30 d of storage. However, the treatment at -1℃ significantly delayed the increase of cell membrane electrolyte leakage and MDA content after 30 days of storage. The activities of superoxide (SOD), ascorbic acid-peroxidase(ASA-POD), catalase (CAT) in the pulp stored at 3℃ reached their peaks at the 20th day and peroxidase (POD) at the 30th day. Storage at -1℃ inhibited the activities of these protective enzymes and reduced their peak values, thereby, significantly slowed down pulp senescence.