杨桃果实过氧化氢酶活性研究

【目的】探讨杨桃果实过氧化氢酶（CAT）的活性及其特性，为杨桃采后保鲜提供理论依据。【方法】以大果甜杨桃为试材，利用紫外可见分光光度计测定杨桃果实CAT活力，分析温度、pH、有机溶剂、金属离子等不同因素对杨桃果实CAT活性的影响。【结果】杨桃果实的CAT活力为0．14U／g·min，其最适温度30℃，最适pH6．6；甲醇和乙醇在低浓度时对杨桃果实CAT活性表现为激活作用，高浓度时呈抑制作用；金属离子Cu2＋对杨桃果实CAT有激活作用，而Mn^2＋和Na^＋对该酶有一定的抑制作用。【结论】杨桃果实CAT活性受温度、pH、有机溶剂和金属离子等因素的影响较明显，生产中通过低温贮藏、合理使用有机溶剂等，可有效延长其货架期。

Research on catalase activity of Averrhoa carambola fruit

Objective ]The catalase （CAT） activity of A verrhoa earambola fruit and its characteristics were investigat- ed to provide theoretical references for its postharvest fresh-keeping. Method]Using big sweet Averrhoa earambola vari- ety as test material,the activity and influencing factors of CAT from Averrhoa earambola fruit were studied by spectropho- tometry. Result]Under the optimum temperature 30℃ and pH 6.6, catalase activity of fruit was 0.14 U/g·min. Methanol and ethanol promoted CAT activity at low concentration, while inhibited CAT activity at high concentration. Metal ion Cu2＋ activated CAT activity, but Mn2＋ and Na＋ inhibited it. Conclusion]Given the fact that CAT activity of Averrhoa carambo- la fruit was immensely influenced by temperature, pH, organic solvent and metal ions, storage duration of Averrhoa earambola could be effectively prolonged when being kept at low temperature and organic solvent rationally used.