Northwest A&F University, College of Mechanical and Electronic Engineering, Yangling, Shaanxi 712100, China.
Northwest A&F University, College of Mechanical and Electronic Engineering, Yangling, Shaanxi 712100, China; Department of Biological Systems Engineering, Washington State University, 213 L.J. Smith Hall, Pullman, WA 99164-6120, USA.
Food Microbiol. 2018 Dec;76:237-244. doi: 10.1016/j.fm.2018.05.015. Epub 2018 May 31.
Infection of Aspergillus flavus, which can produce aflatoxin, is a major problem for peanut safe storage. Thermal inactivation kinetics of Aspergillus flavus is essential to design an effective heat treatment process. In this study, thermal inactivation kinetics of Aspergillus flavus in peanut kernel flour at four water activity (a) levels (0.720, 0.783, 0.846, and 0.921) with three temperatures for each a was studied using a thermal-death-time heating block system and fitted with first-order kinetic and Weibull models. The influence of heating rates on thermotolerance of Aspergillus flavus was also investigated. The results showed that the Weibull distribution model had better coefficient of determination from 0.954 to 0.996, as compared to that (from 0.866 to 0.980) of the first-order kinetic model. An upward concavity was found with the inactivation curve, indicating a tailing effect. Model parameters (D, δ, and p) were estimated with the modified Bigelow equations to predict survival curves of Aspergillus flavus at any temperature and a The reduced heat resistance of Aspergillus flavus at high heating rates above 1 °C/min suggests that developing fast thermal processes is preferred for pasteurizing peanuts in food industry. A case study was presented for applying the cumulated lethal time model to design the industrial heating process based on the thermal kinetics of Aspergillus flavus.
黄曲霉感染会产生黄曲霉毒素，这是花生安全储存的一个主要问题。黄曲霉菌的热失活动力学对于设计有效的热处理过程至关重要。本研究使用热死亡时间加热块系统研究了黄曲霉菌在花生仁粉中的热失活动力学，在四个水分活度（a）水平（0.720、0.783、0.846 和 0.921）下，每个 a 有三个温度，并采用一级动力学和 Weibull 模型进行拟合。还研究了加热速率对黄曲霉菌耐热性的影响。结果表明，与一级动力学模型（0.866 至 0.980）相比，Weibull 分布模型的决定系数更好（从 0.954 到 0.996）。失活动力学曲线呈向上凹形，表明存在滞后效应。使用修正的 Bigelow 方程估计模型参数（D、δ 和 p），以预测黄曲霉菌在任何温度和 a 下的存活曲线。黄曲霉菌在高于 1°C/min 的高加热速率下的热抵抗力降低表明，在食品工业中，巴氏灭菌花生时，优选开发快速热加工过程。本文介绍了一个案例研究，该研究基于黄曲霉菌的热动力学，应用累积致死时间模型来设计工业加热过程。
