Nitrogen compounds and fatty acid composition in seeds of amaranth varieties

Purpose. To determine the peculiarities of the formation of the nitrogen component and the fatty acid composition in amaranth seeds of different varieties. 
Methods. Laboratory (determination of the content of protein, amino acids, fatty acids, carbohydrates), calculation (integral score), mathematical and statistical. 
Results. The conducted studies show that amaranth seeds had a high protein content amounting to 16.1–24.7%. At the same time, it varied significantly over the studied varieties. Thus, significantly higher protein content was in amaranth variety ‘Kharkivskyi 1’ (24.7%) compared to other varieties. The lowest protein content was in ‘Helios’ variety (16.1%). It was found that phenylalanine dominates among essential amino acids in amaranth seeds, with the content ranging in the studied varieties between 981 and 1155 mg/100. The content of tryptophan was the lowest, 155–206 mg/100 g. The highest content of amino acids was determined in variety ‘Kharkivskyi 1’. The seeds of this variety exceeded the seeds of the ‘Helios’ variety by 30–33% in terms of the content of threonine, tryptophan, and isoleucine, by 17–20% of phenylalanine, methionine, and lysine, and by 11% of valine and leucine. In addition, the integral score for the seeds of this variety was also the highest. The highest integral score in the studied varieties was determined for methionine – 33.0–38.9%, for isoleucine – 23.1–30.7, tryptophan, lysine, phenylalanine – 19.4–26.3, leucine and lysine – 16.6–26.3%. The major fatty acid in amaranth seeds is linoleic, the content of which in the seeds of the studied varieties varied significantly, from 2.03 to 2.95 g/100 g. The share of linolenic acid in the seeds ranged from 43.2 to 55.5%. The content of oleic acid varied from 1.60 to 1.33%, with the share of this acid being equal to 23.5–34.0%. The content of linolenic acid was the lowest, 0.01–0.03 g/100 g, with a share of 0.2–0.6% of the total fatty acids. 
Conclusions. Amaranth seeds have the highest percentage of carbohydrates that reach 63.1–68.2% in the studied varieties. The protein content varies from 16.1 to 24.7%. Among essential amino acids, the content of phenylalanine in seeds of the studied varieties was the highest, 985–1155 mg/100 g. The integral score of amaranth seeds for amino acids varied from lowest to highest in the following order: leucine, lysine, threonine, tryptophan, valine, phenylalanine, isoleucine and methionine. The content of fatty acids, varied, respectively: linolenic, stearic, palmitic, oleic and linoleic. According to indicators of the nitrogen-containing component and the content of fatty acids, the seeds of the ‘Kharkivskyi 1’ variety exceed the other studied amaranth varieties.