INFLUENCE OF SOWING TIME, VARIETY AND FERTILIZATION ON THE FRACTIONAL AND AMINO ACID COMPOSITION OF COMMON BEAN GRAIN PROTEIN

Abstract

The influence of sowing dates and fertilization on the amino acid composition of the protein of the grain of common bean varieties Phaseolus vulgaris L. was studied. The value of beans is primarily determined by the increased content of highly soluble and digestible protein in the grain, which is digested better than the protein of other legumes. According to the chemical composition, bean seeds contain, %: protein 17–33, fat – 0.8–3.6, starch – 50–60, fiber – 5–8, sugar – 5–6, ash – about 4%. Bean protein is represented by a large number of valuable amino acids necessary for nutrition, namely, %: arginine – 8.1–9.9, histidine – 2.3–3.6, lysine – 3.4–5.7, methionine – 1.7–1.9, tyrosine – 2.4–3, tryptophan – 0.8–1.8, cystine – 1.2–1.6. Sugars are mainly glucose, fructose and sucrose. Bean seeds also contain minerals, %: K2O – 1.72, Na2O – 0.06, CaO – 0.24, MoO – 0.29, P2O5 – 1.38. The change in the qualitative composition depends on the studied factors. In dry climates, during the growth and development of bean plants, more globulins and less water-soluble proteins accumulate in the seeds, especially during ripening, compared to more favorable conditions. Bean seeds contain all essential amino acids, but some of them are not enough, in particular methionine. In addition, the content of free amino acids is influenced by the conditions of plant nutrition. Thus, increasing doses of nitrogen fertilizers change their indicators. At the same dose of nitrogen, less productive varieties accumulate relatively more protein, compared to highly productive varieties, which differ in the intensity of photosynthetic activity and the ability to synthesize them under conditions of sufficient nitrogen nutrition. The results of the studies showed that depending on the sowing dates, varieties and fertilization, the qualitative composition of bean grain changed. The highest indicators of total nitrogen content were established from sowing 30.04–1.05 and 21–23.05 with average values of 4.36 and 4.30%, respectively. With the introduction of fertilizers, the indicators of total nitrogen from sowing 21–23.04 and 30.04–1.05 were 4.11 and 4.04%. The content of sulfur-containing amino acids in the protein of common beans decreases from early to later sowing dates. In the Mavka variety, the sowing dates did not affect the indicators of this group of amino acids. In the sum of essential amino acids, the largest share is in lysine – 20–25%, leucine – 20–25%, phenylalanine – 14–18%, the smallest – in methionine – 0.4–3.2%.