NO处理对鲜切胡萝卜生理生化变化的影响

摘要

研究以鲜切胡萝卜为对象,采用0.1 mmol/L的一氧化氮(NO)供体硝普钠(sodium nitroprussiate,SNP)浸泡处理2h,测定了其在4℃、贮藏期15d的感官品质和生理生化相关指标的变化,分析了NO处理对鲜切胡萝卜保鲜效果的影响.结果表明,NO有效地降低了鲜切胡萝卜白化发生速率.NO处理能提高抗氧化相关酶活性,如抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)、过氧化氢酶(Catalase,CAT).同时,NO处理降低鲜切胡萝卜组织的电导率、抑制了脂氧合酶(Lipoxygenase,LOX)活性,减少了丙二醛(malondialdehyde,MDA)含量的积累,延迟了膜脂过氧化的发生,减轻了鲜切胡萝卜细胞膜受损程度.另外,NO处理还能够抑制与苯丙烷代谢相关的酶活性,如多酚氧化酶(Polyphenol oxidase,PPO)、过氧化物酶(Peroxidase,POD)、苯丙氨酸解氨酶(Phenylalanine ammonia lyase,PAL)以及总酚、类黄酮等次生代谢物质的积累进而延迟鲜切胡萝卜白化进程.NO通过提高鲜切胡萝卜抗氧化能力、降低与苯丙烷代谢途径相关的酶活性,进而改善了产品的感官质量,延长贮藏期.%Fresh-cut carrots were treated with NO donor sodium nitroprusside (SNP) and soaked with 0.1mmol/L for 2 h.The changes of sensory and physiological and biochemical indexes during 15 d at 4 ℃ were determined.The effect of NO treatment on fresh-cut carrots were analyzed.The results showed that NO effectively reduced the whiteness occurrence rate and improved the antioxidant-related enzyme activity,such as ascorbate peroxidase (Ascorbate peroxidase,APX),catalase (Catalase,CAT).It also reduced the electrical conductivity of fresh-cut carrots'tissue,inhibited the activity of ipoxygenase (Lipoxygenase,LOX),reduced the accumulation of malondialdehyde (Malondialdehyde,MDA),delayed the occurrence of membrane lipid peroxidation,reduced damage of carrots' cell membrane.NO treatment also inhibits enzymatic activities associated with phenylpropane metabolism,such as polyphenol oxidase (Polyphenol oxidase,PPO),peroxidase (Peroxidase,POD),phenylalanine ammonia lyase (Phenylalanine ammonia lyase,PAL);it accumulated secondary metabolites such as total phenols and flavonoids,and delayed the process of fresh-cut carrots' whitening.NO improved the antioxidant capacity of fresh-cut carrots and reduced the enzyme activity associated with the phenylpropane metabolic pathway to improve the sensory quality of the product and prolong the shelf life.