南美白对虾多酚氧化酶的生化特性

对南美白对虾中多酚氧化酶(PPO)的活性及其影响因素作了分析研究,探测该酶的最适pH和最适温度;比较分析了抗坏血酸、亚硫酸钠、植酸和EDTA对PPO的抑制作用以及不同包装连头对虾在不同温度(-2、0、3、7℃)下贮藏期间PPO活性的变化.结果表明:以邻苯二酚为底物,虾PPO活性的最适pH为7.0,最适温度为35℃;4种抑制剂(1mg·mL-1抗坏血酸、2mg·mL-1亚硫酸钠、1mL·L-1植酸及0.1mg·mL-1EDTA)对南美白对虾PPO都表现出一定的抑制作用,以1mL·L-1植酸抑制作用最强;南美白对虾在贮藏过程中PPO活性逐渐上升,真空环境中PPO活性受到抑制,贮藏温度越低,抑制作用越强.

Biochemical characteristics of polyphenoloxidase in prawns

The biochemical characteristics of polyphenoloxidase (PPO) in Penaeus vannamei were studied, and its affecting factors such as pH, temperture and inhibitors were respectively determined. The results were as follows: the activity of prawns was highest under the condition of pH 7.0, 35 ℃ using pyrocatechol as substrate; four inhibitors i.e ascorbic acid(1 mg·mL~(-1)), sodium sulphite(2 mg·mL~(-1)), phytic acid(1 mL·L~(-1)) and EDTA(0.1 mg·mL~(-1)) had some inhibiting effects on the PPO of prawns, in which the effect of phytic acid(1 mL·L~(-1)) was the best; the PPO activity of prawns increased gradurally during the storage period; the PPO activity of prawns was inhibited in vacuum environment, the lower the storing temperature was, the stronger the PPO activity was.