热处理对低温胁迫下黄瓜活性氧代谢和膜脂组分的影响

为探讨热处理减轻黄瓜果实低温冷害的作用机理,本试验研究了47℃热水浸泡5 min处理对黄瓜果实在4℃贮藏期间活性氧代谢和膜脂组分的影响。结果表明,47℃热水5 min处理可显著抑制黄瓜果实冷害的发生,贮藏15 d后果实冷害指数较对照(CK)低20.87%。此外,热处理还可抑制黄瓜相对电导率及丙二醛(MDA)含量的上升,提高黄瓜果实超氧化物歧化酶(SOD)、过氧化物酶(DOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)的活性,抑制超氧阴离子($mathop{{O}}_{2}^{{mathop{}_{ ·}^{-}}}$)及过氧化氢(H₂O₂)的产生,同时降低脂氧合酶的活性,保持较低的饱和脂肪酸含量、较高的不饱和脂肪酸含量和膜脂不饱和度。综上,热处理可维持黄瓜果实活性氧代谢的平衡,抑制膜脂的过氧化作用,从而提高黄瓜果实的抗冷性,减轻果实冷害损伤。

Effect of Heat Treatment on Reactive Oxygen Species Metabolism and Membrane Lipid Constituents of Cucumber Fruit Under Low Temperature Stress

In order to investigate the mechanism of heat treatment in reduce chilling injury of cucumber fruit under low temperature, the effects of immersion treatment with 47℃ hot water for 5 minutes on the active oxygen metabolism and membrane lipid constituents of cucumber fruit during storage at 4℃ were studied. The results showed that treatment with 47℃ hot water for 5 min significantly inhibited the occurrence of chilling injury, and the chilling injury index of treated cucumber was 20.87% lower than that of the control after 15 days of storage. The treatment also inhibited the increase of relative electrical conductivity and MDA content, and increased the activities of superoxide dismutase, peroxidase, catalase and ascorbate peroxidase, and inhibited the production of superoxide anion and hydrogen peroxide. Moreover, the treatment inhibited lipoxygenase activity, maintained lower content of saturated fatty acid and kept higher content of unsaturated fatty acid and membrane lipid unsaturation. These results suggested that heat treatment could keep the balance of active oxygen metabolism and inhibit the peroxidation of membrane lipids in cucumber fruit, thereby improve the cold resistance of cucumber fruit and reduce the incidence of chilling injury.