瞬时高压作用对多酚氧化酶活性的影响  

Effect of Instantaneous High Pressure Process on Polyphenoloxidase Activities

作　　者：刘伟[1,2] 刘成梅[1,2] 钟业俊[1,2] 梁瑞红[1,2] 刘建华[1,2] 

机构地区：[1]南昌大学食品科学教育部重点实验室,江西南昌330047 [2]南昌大学中德食品工程中心,江西南昌330047

出　　处：《食品科学》2006年第10期179-183,共5页Food Science

基　　金：教育部"长江学者和创新团队发展计划"创新团队项目(IRT0540);江西省学科带头人项目(050006);江西省教育厅赣教技字项目(2005J49号)

摘　　要：本文研究了不同条件下瞬时高压作用对多酚氧化酶活性的影响。结果表明:瞬时高压作用对多酚氧化酶具有有效的钝化作用,在pH4.5时,25、35、45℃下分别处理一次,0.1～100MPa时多酚氧化酶活性下降较快,100MPa后活性下降变慢;提高进料温度,可以增强瞬时高压对多酚氧化酶的钝化效果。pH4.5、25℃时,在120、140和160MPa下分别对多酚氧化酶处理三次,在相同的作用压力下,多酚氧化酶活性随处理次数的增加呈下降趋势;多酚氧化酶活性降低幅度随处理次数的增加而变小。常压下多酚氧化酶在pH4.5～6.5时较为稳定,pH值低于4.5时严重失活;140MPa处理后,多酚氧化酶活性较常压下低;活性下降幅度在强酸时更大,其次为强碱,pH4.5时最小。通过检测PPO中酪氨酸和色氨酸的荧光强度发现,微射流均质处理确实使酶蛋白构象发生变化,但是酶活和酶中发色氨基酸的荧光强度之间没有明确的对应关系。This paper studied the effect of instantaneous high pressure（IHP） treatment on polyphenoloxidase activities under different conditions. The results demonstrated that： IHP effectively reduced the activities of polyphenoloxidase. If polyphenoloxidase was treated separately at 25, 35 and 45℃ with pH6, its activity decrease was quick for treating pressure at 0.1-100MPa and slowed down while surpassing 100MPa. Increasing feed-in temperature can augment the reduction of activities of polyphenoloxidase being treated by IHP. At pH4.5 and 25℃, polyphenoloxidase was processed 3 times under 120,140 and 160MPa respectively, and the results showed that under the same pressure, the activity of polyphenoloxidase decreased with processed times, and the decrease extent also became smaller with processed times. Under common atmospheric pressure, polyphenoloxidase was fairly stable when pH was between 4.5-6.5, and its stability is tremendously undermined below pH4.5; when the process pressure was 140MPa, the activity of polyphenoloxidase was lower than that under atmospheric pressure, and furthermore the activity decrease was more obvious under strong acidic condition, while the decrease under strong alkaline condition followed with the smallest decrease being witnessed at pH4.5. By detecting the fluorescence intensity of tyrosine and tryptophan we found that the IHP treatment indeed altered the structure of PPO. But there was no specific corelation between PPO activity and fluorescence intensity.

关 键 词：瞬时高压 多酚氧化酶 

分 类 号：Q814.9[生物学—生物工程]