摘要
本文研究山梨酸钾辅助高压热杀菌(HPTS)对枯草杆菌芽孢的灭活动力学.选用一级动力学模型、Weibull和Log-logistic动力学模型对山梨酸钾辅助HPTS对枯草杆菌芽孢的失活曲线进行动力学模型拟合.分析精确因子(Af)、偏差因子(Bf)、均方根误差(RMSE)、决定系数(R2),在3个模型中,山梨酸钾辅助HPTS的杀菌作用更符合Log-logistic动力学模型(R2=0.986).山梨酸钾(0.2 g/100 mL)辅助HPTS(600 MPa、75℃、25 min)时,失活效果最佳,芽孢致死率为6.10 lg(CFU/mL).山梨酸钾辅助HPTS处理能有效杀灭甜瓜汁中的芽孢,且杀菌后甜瓜汁的褐变度显著降低,贮藏28 d后山梨酸钾(0.1 g/100 mL)辅助HPTS(600 MPa、75 ℃、25 min)处理的甜瓜汁在420 mn处的吸光度达0.093,而HPTS处理的对照样品的吸光度为0.058.通过扫描电镜观察甜瓜汁中枯草杆菌芽孢处理前、后的微观结构,处理后的芽孢形态结构发生变化.结论:山梨酸钾辅助HPTS具有显著的应用价值.
Abstract
In this paper,the inactivation kinetics of potassium sorbate-assisted high pressure thermal sterilization(HPTS)on Bacillus subtilis spores were studied.First-order kinetics model,Weibull and Log-logistic kinetics models were used to fit the inactivation curve of B.subtilis spores by potassium sorbate-assisted HPTS.By analysis of precision factor(Af),bias factor(Bf),root mean square error(RMSE),coefficient of determination(R2),In the three models,Log-logistic Kinetic model fitted best the spore sterilization effect of potassium sorbate-assisted HPTS(R2=0.986).When potassium sorbate(0.2 g/100 mL)assisted HPTS(600 MPa,75 ℃,25 min),the inactivation effect was the best,and the spore inactivation was 6.10 lg(CFU/mL).Potassium sorbate assisted HPTS treatment was applied to the inactivation of spores in muskmelon juice,it was found that the browning degree was significantly reduced,after 28 days of storage,the absorbance of potassium sorbate(0.1 g/100 mL)assisted HPTS(600 MPa,75℃,25 min)at 420 mn reached 0.093,The absorbance of the HPTS-treated control sample was 0.058.Scanning electron microscope was used to observe the microstructure of Bacillus subtilis spores in muskmelon juice before and after treatment,and it was found that the mor-phological structure of the spores changed after treatment.In conclusion,potassium sorbate assisted HPTS has significant application value.
维普
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