Development of a physical-mathematical model for the process of crystallization of meat systems

Abstract

It is proven that the complex of processes that occur during freezing-defrosting of meat systems cannot be described within the framework of the theory of freezing out true solutions. A characteristic feature of meat systems is the heterogeneity in terms of chemical composition, structure and properties. Given this, within the framework of the proposed physical-mathematical model for the process of crystallization, meat system is regarded as a colloidal capillary-porous body. In this case, a process of crystallization is considered as the superposition of two processes: freezing out free moisture (basic process) and a competing process for increasing binding energy for the bound moisture. It was established that the aforementioned processes differently depend on temperature: the speed of freezing out moisture decreases with a decrease in temperature while the rate of the competing process, on the contrary, increases. It was theoretically predicted and experimentally proven that a change in the information parameters of effective specific heat capacity is the criterion of reversibility of the process of low temperature treatment. As revealed by computer simulation, the proposed model more adequately reflects the actual character of dependence of the effective specific heat capacity of meat systems with different composition and properties. Based on the proposed physical-mathematical model for the crystallization of meat systems, we have developed a method for determining effective specific heat capacity (C e ) using the thermograms of freezing-defrosting. Information parameters, which were derived from the temperature dependence of effective specific heat capacity, are: t cr/mel is the temperature of maximum rate of crystal formation (melting), oC; Dt cr is the cryoscopic interval of temperatures, oC; DН cr is the specific heat of phase transition in a cryoscopic interval of temperatures, J/K; Dw is the share of moisture, which changes its aggregate state in a cryoscopic interval of temperatures (the amount of free frozen out or melted moisture). The study conducted became the basis for the scientific substantiation of technologies for manufacturing semi-finished frozen minced meat products for the criterion of reversibility