冰温贮藏对生菜抗氧化能力及贮藏效果的影响

探讨冰温技术对生菜的贮藏效果以及对其抗氧化能力的影响，以采后生菜为试材，4 ℃预冷8 h后装入微孔聚乙烯保鲜袋中，置于温度为（－0.5±0.2）℃的冷库贮藏。贮藏过程中，每3 d测定生菜的抗氧化酶活性、抗氧化物质含量、H2O2含量、O2－?生成速率、丙二醛含量、细胞膜透性、呼吸速率、质量损失率以及叶绿素含量。结果表明：与传统冷藏相比，冰温贮藏显著抑制了生菜呼吸速率；降低了质量损失率；延缓了叶绿素含量的下降速度，并诱导H2O2含量增加，提高了抗氧化酶过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）的活性，减缓了抗氧化物质抗坏血酸含量的下降速率；降低了O2－?生成速率；减缓了细胞膜脂质过氧化损害过程，延缓了丙二醛的积累速度。冰温贮藏可能通过抑制生菜自身代谢提高了生菜抗氧化能力，改善了生菜贮藏保鲜效果。

Effect of Freezing-Point Storage on Antioxidation Capacity and Preservation of Postharvest Lettuce

This study aimed to investigate the effect of freezing-point storage on antioxidation capacity and preservation
of postharvested lettuce. Lettuce were packaged into microporous PE bags and stored at (?0.5 ± 0.2) ℃ for 15 days after
pre-cooling at 4 ℃ for 8 h. The changes in ascorbate peroxidase (APX) and catalase (CAT) activities, ascorbic acid (AsA)
and H2O2 contents, superoxide anion radical formation rate, malondialdehyde (MDA) content, membrane permeability,
respiration intensity, weight losses rate and chlorophyll content were measured. The results indicated that compared
with the traditional storage, freezing-point storage induced an increase in endogenous H2O2 content at the beginning of
storage, enhanced the activities of APX and CAT, postponed the decrease of ASA content, and inhibited the accumulation
of superoxide anion radical, MDA content, respiration intensity, weight losses rate and chlorophyll content. These results
suggest that freezing-point storage may inhibit the metabolic rate and enhance the antioxidant capacity of lettuce, thus
improving its storage quality.