No abstract

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.

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.

The research made it possible to develop a technology for the production of soft beverages using natural vegetable raw materials. To prepare a non-alcoholic natural drink of direct brewing, the following vegetable raw materials were selected: chamomile, orange, lemongrass, valerian, cinnamon, ginger, rose, karkade, rosehip, honeybush. As a result of the study of the composition of the ingredients, it was found that this raw material is rich in vitamins, macro- and microelements, organic acids, tannins, dietary fibers, flavonols and other functional substances. At the same time, they contain a small amount of calories. Due to the presence of benzoic acid in the composition of rosehip fruits, sorbic acid in the composition of orange, the drink will be stabilized, since they are natural preservatives. Also, orange peel, karkade give the drink a taste and a pleasant aroma. Thus, the considered raw materials are a favorable object to create a soft drink based on them. Beverages based on these natural herbal ingredients will be in demand among people who take care of their health. During the experiment, three experimental blends were made for two beverages, with different contents of chamomile, orange, lemongrass, valerian, cinnamon, ginger and rose, karkade, rosehip, honeybush, lemongrass. According to the organoleptic parameters, one option was selected for each drink. The organoleptic and physico-chemical parameters of the finished product - a natural soft drink of direct brewing - have been studied. Based on the conducted research, a technological scheme for obtaining a soft drink based on the direct brewing method was modeled. Technological documentation for beverages has been developed.