CONTROL OF PROTEIN CONTENT IN SOYBEAN CULTIVATION PROCESS IN UZBEKISTAN

Background. Protein is the main biochemical component of soybean seeds. Soybean is one of crops cultivated in the world that have high protein content. According to various authors, the seeds of this culture can accumulate an average of 38–42% protein with a variation of this indicator from 30 to 50%. Soy is not only a source of protein, but also oil, the content of which in the seeds ranges from 16 to 27%. Low carbohydrate content is typical for soy plant. The soybean protein has a balanced ratio of essential amino acids and is equal to the protein of eggs and meat. Purpose. The goal of the present research is to recommend to breeders the promising soy varieties cultivated in Uzbekistan basing on quantitative content and characterization of proteins. Methodology. The soybean seeds were defatted with acetone and ether at low temperature. The total protein was isolated from the defatted soy flour (powder) by alkaline extraction. The comparative quantitative protein content was determined by the spectrophotometric method of Kalkar. Electrophoresis in a 10% polyacrylamide gel in the presence of marker proteins was performed to determine the molecular weight ofthe subunits for proteins isolated from the new soybean varieties. IR spectral analysis of proteins from the studied soybean varieties was carried out to compare the absorption in the spectral region of 1650 cm-1. Originality. Data on the quantitative content of protein in 10 new breeding varieties of soybeans created in the Tashkent Scientific Experimental Station of Rice, Grain and Bean Crops were obtained for the first time. Findings. The quantitative determination of protein by the spectrophotometric method of Kalkar was carried out in new soybean varieties. Three varieties were high-protein, contained in their composition more than 30% of protein. Electrophoresis in 10% polyacrylamide gel in the presence of protein markers provided a comparative fractional composition of proteins of the studied soybean varieties. It was shown that highprotein soybean varieties have a lower content of low molecular weight proteins. The slight discrepancy was observed in the region of oscillation of 1650 cm-1 in comparative study of IR spectra of contrasting varieties. Highlights: - isolation of total protein from defatted soy flour, comparative quantitative determination by the Kalkar’s method; - comparative study of the studied soybean varieties proteins fractional composition by electrophoresis.