辣椒粉中黄曲霉菌生长及其产毒规律的预测模型构建

Prediction Model Construction for Aspergillus flavus Growth and Toxin Accumulation in Chili Powder

为掌握黄曲霉菌在辣椒粉基质中的生长及产黄曲霉毒素规律,检测温度为20、28、37、45℃,水分活度为0.85、0.90、0.93、0.97及pH值为4.5、5.0、5.5环境因子条件下菌株生长及毒素累积数据。采用Baranyi and Roberts模型估计速率菌落最大径向生长(μ_(max),mm/d),采用修正的二阶多项式模型、Arrhenius模型及三阶多项式模型描述环境对μmax的综合影响。同时构建环境、时间与黄曲霉毒素含量的二阶多项式模型。结果表明对黄曲霉生长,修正的二阶多项式模型拟合效果最优,决定系数(R^(2))>0.99,偏离因子(B_(f))、精确因子(A_(f))分别为1.0770和1.1319。对黄曲霉毒素累积量也达到了较优预测,R^(2)>0.97。研究结果可为辣椒粉的安全储藏及加工提供可借鉴的基础数据,并为延长辣椒粉货架期提供理论依据。

In order to understand the pattern of growth and aflatoxin production of Aspergillus flavus in chili powder matrix,the growth and toxin accumulation data were obtained under varying conditions of temperature(20,28,37 and 45℃),water activity(0.85,0.90,0.93 and 0.97)and pH(4.5,5.0 and 5.5).The Baranyi and Roberts model was used to estimate the maximum radial growth rate(μ_(max),mm/d)of colonies.The modified second-order polynomial model,Arrhenius model and third-order polynomial model were used to describe the combined influence of the environmental factors onμmax.Moreover,a second-order polynomial model was developed depicting the effect of the environmental conditions and culture time on aflatoxin production.The results showed that the modified second-order polynomal model had the highest goodness of fit to determine the growth of A.flavus,with coefficient of determination(R^(2))larger than 0.99.When comparing observed and predicted values of A.flavus,the bias factor(B_(f))and accuracy factor(A_(f))were found to be 1.0770 and 1.1319,respectively.The cumulative amount of aflatoxin was accurately predicted by the proposed model with R^(2) greater than 0.97.These results can provide basic data for the safe storage and processing of chili powder,and also provide a theoretical basis for extending the shelf life of chili powder.