連續式粒體食品低壓過熱蒸汽殺菌模擬與分析

Abstract

蒸汽被廣泛地應用於食品加工，由於蒸汽的潛熱以及其表面對流係數很大，使用蒸汽來加熱的處理食品的效率十分地高。食品本身的口味和香氣是飲食中非常重要的部分，但高溫處理或是長時間加熱可能會破壞食品本身的風味或是降低食品的品質。低壓飽和蒸汽或低壓過熱蒸汽可以提供加熱溫度低於100ºC的加熱媒介，從而防止食物因高溫而失去其風味。本研究的主要目的是驗證連續式反應器對顆粒狀食品進行巴氏殺菌的熱質傳數學模型。蒸汽殺菌的過程類似於蒸汽乾燥，所以本研究的數學模型是基於蒸汽乾燥動力學進行改寫。本研究使用商業有限元素法軟體（COMSOL Multiphysics）進行數學計算和並利用球形樣本的加熱曲線作模型的驗證。從結果可知建立一個小規模的反應器來進行塞流反應器模擬是的可行的。

Steam is widely applied in food process industry. In some researches, steam is mentioned to be the most efficient media of heating because of its high latent heat and surface convection coefficient. The taste and flavor of food products are very important parts in our diet, but high temperature or prolong heating might damage food quality and flavor. Low-pressure saturated or superheated steam under low pressure can provide heating temperature below 100 ºC thus prevent food from losing its taste or flavor. The main objective of the study is to modeling heat and mass diffusion in particulate food under continuous low pressure pasteurization and device a simulator for validation. The steam pasteurization is similar to steam drying, so the model is modified based on steam drying kinetics. The mathematical model of low-pressure steam pasteurization in spherical food is a coupled model of heat and mass transfer adapted from to our previous model on porous food. Mathematical simulation was established by using commercial FEM software (COMSOL Multiphysics) and spherical particles were steam heated in the simulator for temperature history validation. The results show the possibility of establishing a small scale reactor to simulate plug flow reactor.