热穿透测定法和公式法在建立冻虾仁杀菌模型中的比较研究

A comparative Study on the Establishment of Sterilization Model of Frozen Shrimp by Heat Penetration Method and Formula Method

为建立并验证公式法建立冻虾仁杀菌模型的可行性,研究首先通过热穿透测定法测定产品内冷点位置在热力杀菌过程中的加热特性,建立标准杀菌模型;然后利用长圆柱体不稳定传热原理,结合产品传热参数,计算产品冷点位置的加热特性参数,建立杀菌模型。最后,验证2种杀菌模型的一致性以及公式法代替热穿透测定法的可行性。结果表明,公式法可以高精度模拟杀菌温度曲线,其中心温度和杀菌强度F值的均方根误差RMSE无显著差异,结果比热穿透测试法保守。此外,使用公式法解释产品中心温度T和关键因子,即杀菌时间t和产品直径d的关系:T=—1.630d+0.768t+39.42。最后通过公式法计算出不同规格冻虾仁(个/磅)41~50、51~60、61~70、71~90、91~110、111~200的安全杀菌时间(杀菌温度95℃)分别为130、120、110、100、90 s和60 s。从安全角度出发,利用公式法建立冻虾仁杀菌模型是可行的。

In order to establish and verify the feasibility of the formula method to establish the sterilization model of frozen shrimp,the standard sterilization model was established by heat penetration method,which measured the heating characteristics of the product’s internal cold point in the process of thermal sterilization.Then the long cylinder unstable heat transfer principle and the heat transfer parameters were combined to calculate the heating characteristic parameters of the internal cold point,by which the sterilization model was established.Lastly,the consistency of two kinds of sterilization models and the feasibility of heat penetration method replaced by formula method were verified.The results showed that the sterilization temperature curve was simulated by formula method with high precision,and there was no significant difference in RMSE of center temperature and the sterilization intensity F value.In addition,the results of F value were more conservative than the heat penetration method.Meanwhile,the relationship between product center temperature T and the key factor sterilization time t and product diameter d were also explained by formula method:T=—1.630 d+0.768 t+39.42.The safe sterilization time of 41~50,51~60,61~70,71~90,91~110 and 111~200 specifications frozen shrimps were 95℃,130 s,120 s,110 s,100 s,90 s and 60 s respectively by formula method.Therefore,from the perspective of safety,the formula method is feasible to establish the sterilization model of frozen shrimp.