中短波红外线对胡萝卜粉的杀菌效果及动力学分析

Bactericidal Effect and Kinetics of Short- and Medium-wave Infrared Radiation on Carrot Powder

本文研究了中短波红外线分别在100℃、110℃、120℃条件下处理1 min、2 min、3 min、4 min和5 min对胡萝卜粉菌落总数、霉菌酵母的杀菌效果及杀菌动力学,并探讨了对胡萝卜粉水分含量和色泽的影响。研究表明：随着温度的升高和时间的延长,杀菌效果增强,霉菌、酵母对温度较为敏感,120℃处理3 min时可全部杀死;水分含量降低,有利于贮藏时间的延长;色差值变大,尤其110℃处理4、5 min和120℃处理2 min以上,色差值显著增加。应用Weibull模型对不同处理条件下胡萝卜粉的杀菌效果进行拟合,动力学曲线的决定系数R2均大于0.98,χ~2、RMSE的值均不高于0.01和0.40,拟合效果较好。综合考虑杀菌效果,对水分含量、色泽的影响以及设备运行成本,认为中短波红外线对胡萝卜粉杀菌处理的较适宜条件为120℃处理1 min。

The total colony number, the bactericidal effect against mold and yeast, and bactericidal kinetics were studied, after short and medium-wave infrared radiations were applied on carrot powder at various temperatures（100 ℃, 110 ℃, and 120 ℃） for 1, 2, 3, 4, and 5 min. The effects of the treatments on carrot powder moisture-content and color were evaluated. The results showed that the bactericidal effects of infrared radiation were strengthened with increasing temperature and time; mold and yeast were more sensitive to temperature and could be inactivated by subjecting to 120 ℃ for 3 min, and the resulting decrease in moisture content was beneficial for prolonging storage time. The color difference value was increased after infrared radiation, particularly by treatments at 110 ℃ for 4 min and 5 min or 120 ℃ for 2~5 min. The Weibull model was used to fit the survival curve for bacteria grown on the carrot powder subjected to different treatments. The correlation coefficients（R2） of kinetic curves determined at three temperature levels were higher than 0.98, and the values of χ2 and root-mean-square error（RMSE） were less than 0.01 and 0.40, respectively, indicating a good fit. Based on the bactericidal effect, the effects on water content and color, and the equipment operating cost, the optimal conditions for microbial inactivation of carrot powder using short- and medium-wave infrared radiation was determined to be 120 ℃ for 1 min.