超高静压对非浓缩还原杨梅果汁中氧化酶的钝化作用

该研究以非浓缩还原（not from concentrate，NFC）杨梅果汁为研究对象，研究不同超高静压（high hydrostatic pressure，HHP）处理（300~600 MPa/0~30 min）对NFC杨梅汁中多酚氧化酶（polyphenol oxidase，PPO）和过氧化物酶（peroxidase，POD）的影响。对比传统高温灭酶，拟合建立HHP压力与酶活性的一级动力学回归方程，分析得到相关参数（压力脉冲效应PE、压力脉冲数值ND、等效破坏值Dp及酶的失活速率K）。结果表明，较高压力（400~600 MPa）对PPO与POD均起到钝化效果，其中600 MPa/10 min能钝化90%的PPO活性，600 MPa/20 min钝化80%的POD活性。600 MPa/30 min条件下，重复加压不能明显加强钝化效果。将PPO和PPO活性与压力进行一级动力学拟合，得到相应线性回归方程（R2>0.8）。随着压力从300 MPa升高到600 MPa，PPO的K值从3.03×10-2升高到12.12×10-2，POD的K值从1.23×10-3上升到7.67×10-3。600 MPa条件下，PPO和POD的ND分别为1.04和1.59，Dp值都为19。同时，压力和保压时间及其相互作用对PPO和POD活性的影响均有极高的显著性（p<0.001）。因此，HHP对杨梅果汁中关键的氧化酶能起到较好的钝化作用，能够为NFC杨梅汁加工技术的应用提供科学依据。

Effect of High Hydrostatic Pressure Treatment on Inactivation of Oxidase in Non-concentrated Bayberry Juice

The effect of different high hydrostatic pressure (HHP) treatments (300~600 MPa/0~30 min) on polyphenol oxidase (PPO) and peroxidase (POD) in non-concentrated (NC) bayberry juice was studied. Compared to the traditional heat inactivation, the relationship between HHP treatment and enzyme activity was established by fitting the first-order kinetic regression equation and relevant parameters (pressure pulse effect PE, pressure pulse number value ND, equivalent damage value Dp and inactivation rate K of enzyme) were obtained. The results showed that higher pressure (400~600 MPa) had inactivation effects on PPO and POD, in which 600 MPa/10 min could inactivate 90% of PPO activity and 600 MPa/20 min could inactivate 80% of POD activity. Repeated cycle at 600 MPa/30 min did not increase the passivation effects. The linear regression equation (R2>0.8) was obtained by fitting PPO and PPO activity with pressure. With the increase of pressure from 300 MPa to 600 MPa, the K value of PPO increased from 3.03×10-2 to 12.12×10-2, and the K value of POD increased from 1.23×10-3 to 7.67×10-3. At 600 MPa, the ND of PPO and POD were 1.04 and 1.59, respectively, and the Dp values were 19. At the same time, the effects of pressure, holding time and their interaction on PPO and POD activity were extremely significant (p<0.001). Therefore, HHP had a good inactivation effect on the key oxidase in bayberry juice, which could provide a scientific basis for the application of HHP in NC bayberry juice processing.