复合抑制剂对核桃青皮多酚氧化酶活性的影响

摘要

In order to provide some references for inhibiting browning of walnut during picking,production and processing,polyphenol oxidase (PPO) was extracted from green husks of walnut (Juglans regia),and effects of different inhibitors and their complexes on PPO activity were studied by spectroscopy.The results showed that the effect of inhibitors on PPO activity had obvious differences,the optimal inhibition concentrations of Na2SO3,NaC1,L-Cys and rutin to PPO activity in green husk of walnut were respectively 0.3,0.6,0.3,0.3 mol/L,in which inhibition effect of L-Cys to PPO activity was most significant.The results of orthogonal test showed that the inhibition effect of mixed solution of 0.4 mol/L Na2SO3,0.5 mol/L NaCl,0.2 mol/L L-Cys and 0.8 mol/L rutin to PPO activity was the best.Conclusions:PPO in green husk of walnut was main enzymes causing browning;PPO activity could be inhibited by adding L-Cys or inhibitor complexes during picking,production and processing of walnut.%为给核桃采摘、生产及加工中褐变现象的抑制提供理论参考依据,从核桃青皮中提取多酚氧化酶(PPO),采用光谱法研究了不同抑制剂及其复合物对其PPO活性的影响情况.单因素试验结果显示:不同抑制剂对核桃青皮PPO酶活性的影响差异明显,亚硫酸钠(Na2SOa)、氯化钠(NaCl)、L-半胱氨酸(L-Cys)、芦丁对核桃青皮PPO活性的最适抑制浓度分别为0.3、0.6、0.3、0.3 mol/L,其中,L-Cys对其PPO活性的抑制效果最为显著.正交试验结果表明:以0.4 mol/L的Na2SO3、0.5 mol/L的NaCl、0.2 mol/L的L-Cys和0.8 mol/L的芦丁配制的复合液对其PPO活性的抑制效果最好.文中综合分析认为,核桃青皮PPO是引起其酶促褐变的主要影响因素,在核桃采摘、生产及加工中可通过添加L-Cys或多种抑制剂的复合物来抑制其PPO活性.