LAUSR

Drinks are important in the human diet. The most promising ones include fermented beverages enriched with bioactive substances of their raw materials and with products of their fermentation. Gluten-free foods, too, are becoming popular as there are more and more people worldwide suffering from coeliac disease. The paper presents the results of theoretical and experimental research on developing a technology of a fermented soft drink based on rice as a gluten-free raw material. The domestic cultivars of husked and unhusked rice described in the paper are Agat, Prestizh, and Premium. Their physical, biological, and physicochemical parameters have been studied, and their amino acid and vitamin composition, the content of macronutrients and trace elements have been determined. According to the research results, it is practical to use rice of the Agat variety in the technology of fermented beverages. Compared with the samples of Premium and Prestizh, the extractivity of Agat is higher by 2–5%, and as to the soundness of its kernels and the husk content, it exceeds them, respectively, by 2.5 and 5.5%. The fat content, which reduces the amount of esters formed during fermentation and adversely affects the foam retention of a drink, was lower in Agat by 28–37%. The content of protein compounds, vitamins, macronutrients and trace elements in grain is essential for the technology of fermented beverages. It has been established that Agat is higher in amino acids than other varieties are: by 5.7% (husked) and by 18% (unhusked). The highest content of vitamins has been found in Agat rice (on average, by 9.4% more of them). Compared with the other cultivars, unhusked Agat rice is higher in the macronutrients and trace elements that are vital for yeast activity: calcium – by 28%, magnesium – by 24%, iron – by 10–18%, copper – by 16.6%. The optimal initial concentration of yeast cells in the wort is 3–5 million/cm3. When using husked rice, the acidity of the wort at the end of fermentation was higher by 7.6% than it was in the wort made with unhusked rice. When comparing different varieties of rice, the acidity values of the fermented wort did not differ significantly. All samples had high sensory qualities characteristic of fermented beverages.