超高压对泡萝卜的杀菌效果及其动力学研究

研究300~600 MPa超高压条件下处理四川泡萝卜5~25 min,对其细菌总数的影响、对霉菌、酵母菌及大肠菌群的杀灭效果的影响。并采用3种模型对不同压力条件下杀菌动力学过程进行分析比较。结果表明:随处理压力和时间的增加,超高压对泡萝卜的杀菌效果增强;霉菌和酵母菌对压力较为敏感,500 MPa处理5 min可被全部杀死;Weibull模型能很好地拟合泡萝卜超高压杀菌的动力学过程(决定系数R20.99),且相较Log-logistic模型更简洁、灵活实用。尺度参数b随处理压力的增加而增大,形状参数n则随压力的增加而减小。

Inactivation and Kinetics Analysis of Microorganisms in Pickled Radish Processed by High Hydrostatic Pressure

In order to explore the inactivation effect of high hydrostatic pressure on naturally occurring microorganisms in
pickled radish, the numbers of aerobic bacteria, mold and yeast as well as coliform in pickled radish were measured after
pressure processing at various pressure levels (300–600 MPa) for 5–25 min, respectively. The traditional linear models,
Weibull and Log-logistic model were used to fit the survival curves of aerobic bacteria in pickled radish processed by high
hydrostatic pressure. The results showed that microbial inactivation was improved with an increase in pressure level and
processing time. Both mold and yeast were more sensitive to pressure processing and could be inactivated by 500 MPa
pressure for 5 min. Modeling analysis showed that the coefficient of determination (R2) were higher than 0.99, indicating
that the Weibull model fit the kinetics curve of aerobic bacteria inactivation well. The Weibull model was more simple and
flexible compared with the Log-logistic model. The value of scale factor b of the Weibull model increased with increasing
pressure, while the value of shape factor n decreased.