机构地区: 韩山师范学院
出 处: 《湖北农业科学》 2007年第6期999-1002,共4页
摘 要: 以品种为红皮白肉的火龙果果肉为材料,对火龙果果肉中的多酚氧化酶(PPO)的特性进行了初步研究。通过其催化邻苯二酚氧化后产物的吸光度值的测量,分别研究了pH值、温度、反应时间以及肉桂酸、L-半胱氨酸、柠檬酸和抗坏血酸4种抑制剂等条件对PPO活性的影响。结果表明,以0.2 mol·L-1的邻苯二酚为底物时,其最适波长为410 nm,最适pH值为6.8,最适温度为30℃,温度超过50℃时该酶的活性明显降低,反应时间不宜超过15 min。在较短时间内几种添加剂对火龙果PPO的活性均表现出不同的抑制作用,其中以L-半胱氨酸的效果最为理想,而且2种添加剂协同作用时以L-半胱氨酸+抗坏血酸的效果最为理想。 The activity of pitaya polyphenol oxidase (PPO) was determined by speetrophotometer using 0.2mol· L^-1 eateehol as substrate. The effects of the PH,temperature,reactivity time and inhibitors such as 4-Hydroxycinnamic acid, L-cysteine, citricacide and Vic were studied. The results showed that the optimum conditions were as follows: k=410nm,pH=6.8,T=30℃, the time of reactivity 〈15min. When T〉50℃ ,the PPO activity descends obviously. Among the four inhibitors, the optimum one is the L-cysteine.