No abstract

The development of functional foods with specified beneficial properties is one of the main directions in the problem of maintaining and preserving the health of the population. To solve this problem in the diet include products produced using dietary supplements made from natural ingredients. In addition, the problem of creating food with a certain texture made it possible to isolate thickeners and gelling agents food additives that regulate the consistency and form the structure of the product. The department of technology of meat, dairy products and chemistry of the Bashkir State Agrarian University developed two functional combined products, dairy and vegetable yogurt: 1 using dried horse milk and 2 using dried horse milk and vegetable component, pumpkin seed flour, identified their physicochemical properties and the proposed method for studying structure formation in fermented milk products. The study on the example of yoghurt 1 proved that when lactic acid fermentation proceeds, a decrease in the carbohydrate content of the product leads to an increase in its acidity and this causes a change in the consistency of the product. As a result, a ferment with lactic acid bacteria, producing exopolycarbohydrates, dried mare's milk and a vegetable component from pumpkin flour containing pectins, turned out to be good thickeners and gelling agents. All of the above components of yogurt are natural raw materials, so they can be used as safe food additives in the production technology of fermented milk products. In addition, the introduction of dried mare's milk contributes to the correction of the protein composition of the milk mixture, and the use of pumpkin seed flour in the production of yogurt enhances the beneficial properties of yogurt. This research is very relevant from the point of view of developing useful functional products.

At present, there are no reliable criteria for acceptable drying temperatures; so, a new approach is proposed to determine the range of acceptable drying conditions based on a joint solution of the equations that determine the drying kinetics and the kinetics of changes in the process characteristics of the product. For a given product quality, the logarithm of the maximum allowable drying time linearly depends on the reciprocal of the absolute temperature of the drying agent. The method for calculating the drying time is simplified based on a new product characteristic - equivalent moisture content. The criterion of acceptable conditions, which is the maximum temperature of the drying agent, is a function of the magnitude of the thermal effect, the parameters of the drying kinetics, and the kinetics of the process properties of the product.

It is shown that the existing approaches to drying process modeling, based on a system of interconnected differential equations of heat and mass transfer or on statistical processing of drying process experimental data, have significant drawbacks. It greatly complicates the development of computer means for controlling production processes. During modeling it is proposed to consider drying process from the standpoint of physical chemistry as a quasi-topochemical heterogeneous reaction and perform mathematical modeling of this process based on the laws of chemical kinetics. The basic issues of methodology of drying process modeling based on the laws of chemical kinetics are reviewed: the study of the equation of drying rate during the removal of free and bound moisture; methods for determining composition of the aqueous fractions with different forms and energy of moisture in materials; methods of determination of an activation energy of moisture; the influence of the concentration of moisture and other process factors on the drying speed. The methodological approach considered in the article allows developing reliable mathematical models of drying kinetics for the purposes of computer technologies for managing production processes and avoiding the errors that the authors note in previously published works.

The article deals with issues related to the study of the connection forms of moisture removed during the drying process of thermolabile heterogeneous products. The difficulties, emerging while developing drying process controlling methods, optimizing energy, material costs, and temperature regimes, necessitate further research. It is shown that the existing methods of studying the forms of moisture connection with the material have significant drawbacks and generally give a qualitative assessment of the state of moisture in the material or are very time-consuming and require long-term laboratory studies. An approach to determining the forms of moisture bond in the material based on graph-analytical analysis of the drying kinetics is proposed, which allows qualitative and quantitative assessment of the state of moisture in the product. With the help of a graphical editor, typical drying kinetics curves were processed and the dependences of the value that characterizes the speed of change in the drying rate on the moisture content of the product were obtained. It is proposed to introduce a new value in the drying theory - drying acceleration. The analysis of the obtained curves testifies to the presence of extremes and inflection points corresponding to the critical moisture content, as well as the presence of areas with slowing or accelerating changes in the drying rate, allowing setting intervals for removing moisture with different binding energy. The approach considered in the article to determining the forms of moisture communication in the material will not only give a qualitative and quantitative assessment of the state of moisture in products, but also reduce the time for analysis and improve the accuracy of the results.