蛋清液中大肠杆菌超声协同热处理杀菌动力学研究

利用超声协同热处理蛋清液,研究其对蛋清液中大肠杆菌的杀菌效果,运用Weibull模型对杀菌动力学过程进行分析,确定该种处理方法对蛋清液主要功能性质的影响。研究结果表明,随着功率(100~600 W)的增大、温度(45.0~57.5℃)的升高和处理时间(2~5 min)的增加,超声协同热处理对蛋清液中大肠杆菌的杀菌效果显著增强(P<0.05)。具体表现为:超声功率由100 W增加至600 W(50.0℃,3 min)时,大肠杆菌菌体浓度降低量由0.67 lg CFU/m L增加至1.24 lg CFU/m L;热处理温度由45.0℃增加至57.5℃(600 W,3 min)时,大肠杆菌菌体浓度降低量由1.01 lg CFU/m L增加至1.80 lg CFU/m L。利用Weibull模型对杀菌动力学过程拟合并简化,得到的Weibull模型拟合性较好,能够预测超声协同热处理不同功率-温度-时间的杀菌动力学过程,可为蛋清液在超声协同热处理过程中微生物安全性的控制提供理论依据。当超声功率为300 W(55.0℃,3 min)时,与对照组相比,蛋清液的凝胶硬度提高了101.04%,起泡力提高了50%。超声协同热处理可有效控制蛋清液中的微生物含量,并在一定程度上改善蛋清液的功能性质。

Inactivation Kinetics of Escherichia coli in Egg White Liquid by Ultrasonic-assisted Heats Treatment

The effect of ultrasonic-assisted heats treatment on Escherichia coli and functional properties in egg white liquid was investigated.The inactivation kinetic of Escherichia coli was analyzed by fitting with Weibull model.The result showed that the reduction in Escherichia coli was enhanced with an increase in ultrasonic power,temperature or time.The reduction in Escherichia coli was enhanced from0.67 lg CFU/m L to 1.24 lg CFU/m L with the increase of ultrasonic power from 100 W to 600 W(50.0℃,3 min).The reduction in Escherichia coli was enhanced from 1.01 lg CFU/m L to 1.80 lg CFU/m L with the increase of temperature from 45.0℃to 57.5℃(600 W,3 min).The Weibull model provided a good fit to the inactivation curves of Escherichia coli at different ultrasonic-assisted heats treatment.The simplified Weibull model could be used to predict the process of ultrasonic-assisted heats treatment inactivation kinetic of Escherichia coli and provide a theoretical basis of microbial safety control in the ultrasonic-assisted heats treatment processing of egg white liquid.At the same time,when the ultrasonic power was 300 W(55.0℃,3 min),the gel hardness was increased by 101.04%,while the foam capacity was increased by 50%.In conclusion,ultrasonic-assisted heats treatment could control the microbial content of egg white liquid effectively and improve the functional properties.