高压均质对芒果汁中大肠杆菌的杀菌动力学

为预测高压均质(high pressure homogenization,HPH)对芒果汁中大肠杆菌的杀菌作用,进行了压力40~190 MPa、进料温度20~60℃和均质次数1~5次的HPH实验,并运用Weibull模型对杀菌致死曲线进行动力学分析。研究表明:随压力、进料温度和均质次数的升高,HPH对芒果汁中大肠杆菌的杀菌效果增强。50℃HPH处理芒果汁,压力由40 MPa升高至190 MPa时,大肠杆菌降低量由0.46(lg(CFU/mL))增加至5.16(lg(CFU/mL)),达到美国食品药物管理局规定的非热加工杀菌卫生安全要求;70 MPa HPH处理芒果汁,进料温度由20℃升高至60℃时,大肠杆菌降低量由0.34(lg(CFU/mL))增加至5.02(lg(CFU/mL));20℃、190 MPa HPH处理芒果汁,均质次数由1增加至4时,大肠杆菌降低量由1.73(lg(CFU/mL))增加至5.15(lg(CFU/mL))。通过Weibull模型拟合杀菌致死曲线,并对模型进行简化,发现简化的Weib ull模型在20~50℃、40~190 MPa均质1次和20~40℃、190 MPa均质1~5次时拟合性较好(R~20.92)。简化的Weibull模型可用于预测进料温度-压力和进料温度-均质次数的杀菌效果,可为芒果汁的HPH生产过程中微生物安全性的控制提供理论依据。

Inactivation Kinetics of Escherichia coli in Mango Juice by High Pressure Homogenization

The inactivation kinetics of Escherichia coli in mango juice by high pressure homogenization (HPH) wasfitted with the Weibull model to predict the inactivation effect in this study. E. coli was subjected to HPH treatments (inlettemperature: 20–60 ℃; pressure: 40–190 MPa, and passes: 1–5). The reduction in E. coli was enhanced with increasingpressure, inlet temperature or number of passes. The reduction in E. coli in the sample after one pass at 50 ℃ was enhancedfrom 0.46 to 5.16 (lg(CFU/mL)) with pressure increasing from 40 to 190 MPa, which reached the hygienic requirementsfor non-thermally processed food claimed by the US food and drug administration. The reduction in E. coli after one passat 70 MPa was enhanced from 0.34 to 5.02 (lg(CFU/mL)) with inlet temperature rising from 20 to 60 ℃. The reduction inE. coli at 190 MPa and 20 ℃ was enhanced from 1.73 to 5.15 (lg(CFU/mL)) with increasing number of passes from 1 to 4.The Weibull model provided a good fit to the inactivation curves of E. coli at different HPH treatments, with R2 > 0.90. Thesimplified Weibull models were fitted well under 20–50 ℃/40–190 MPa for one pass and 20–40 ℃/190 MPa for 1–5 passes(R2 > 0.92). The simplified Weibull models to predict HPH inactivation kinetics of E. coli could provide a theoretical basisfor microbial safety control in the HPH processing of mango juice.