PHYSICAL JUSTIFICATION OF THE PARAMETERS OF OSMOTIC DEHYDRATION AS A METHOD OF PROCESSING ROOT VEGETABLES

Abstract

The article presents the results of an experimental study of osmotic dehydration of root vegetables. Ripe root vegetables were used as the subject of the study Daucus (Chantane), Beta vulgari (Bordeaux 237), Pastináca sátiva (White stork). Sugar solutions of various concentrations (50, 60, 70%) were used as an osmotic solution. The experiment was carried out at different temperatures (40, 50, 60 ° C) and with different duration of the process (1; 1.5; 2; 2.5 h). Research has shown that vegetable particles less than 5 mm in size can boil over and have an unattractive wrinkled shape and dry consistency after drying. Particles with a size of 10 mm have a characteristic shape, but even after 2.5 hours of dehydration, there is a noticeable smell and taste of vegetables, which negatively affects the sensory indicators of quality. The proposed grinding of vegetable raw materials into cubes of 5×5×5 mm, which provides the same diffusion path and good organoleptic properties of the finished product for all types of investigated vegetables. Based on the results of experimental studies and mathematical calculations, the optimal parameters for conducting the process of osmotic dehydration in the production of candied vegetables have been determined. It was found that the greatest dynamics of dehydration is observed during the first time of dehydration, when the difference in sucrose concentrations in the osmotic solution and inside the particles is greatest. The greatest mass transfer is observed when using a solution with a sucrose content of 70%. This concentration of the osmotic solution creates a sufficient osmotic potential, thereby leading to a greater loss of water, slowing down oxidative and non-enzymatic browning, resulting in a better product. Active mass transfer occurs in the first 2 hours, so the process can be limited to this period, since further dehydration is economically and technologically inexpedient. It is mathematically proven that osmotic dehydration of vegetables occurs faster when mixing the sugar solution, by reducing the resistance to mass transfer on the surface and avoiding localized dilution, which affects the rate of water removal.