Determination of optimal technological parameters of obtaining stevia extract in technology of sour dairy desserts

Abstract

In order to determine the optimal technological parameters for obtaining stevia leaf sweet extract, the dependence of the extractives' yield on the temperature and extraction process duration was investigated. A mathematical model has been built that makes it possible to determine and predict the extraction process at different technological parameters in order to effectively obtain extractive substances. The expediency of using whey from the production of fermented milk cheese as an extractant for obtaining stevia extract has been substantiated. It was experimentally established and mathematically confirmed that the use of whey makes it possible to increase the yield of extractives by 12.1 %, as opposed to the use of an aqueous solution. In order to intensify the extraction process, it is proposed to use a rotary-pulse apparatus. It was found that the application of a rotary-pulse apparatus makes it possible to increase the yield of extractive substances from sweet grass by 0.1–0.4 % compared to maceration. The optimal technological parameters for obtaining stevia extract have been determined: hydro module, 1:15; extractant, whey; extraction temperature, 85±5 °С; process duration, 20–25 min. The use of graphic and mathematical modeling in the environments "Mathcad" and "Statistica" helped construct 3D-graphic models to illustrate the dependence of the degree of extraction of extractive substances from dry stevia leaves on the technological parameters for obtaining extracts. The improved technology of obtaining stevia leaf sweet extract will significantly expand the range of "healthy foods" through the partial or complete replacement of sugar. The production of such dietary products will have a social effect and economic attractiveness for food industry enterprises