[Biological value of various types of dietary soy bean proteins]

Chemistry and experiments on animals (male Wistar rats) were made to determine the biological value of 4 samples of soybean proteins: 2 protein isolates (Ardex SP-6 and Ardex-M, ADM USA); soybean protein concentrate (UNICO, UNIMILS, Holland), and textured soybean concentrate (manufactured by the All-Union Research Institute of Fat). The content of essential amino acids and amino acid score of the protein samples were measured relative to three standard aminograms. The "growing" (the protein efficacy ratio and net protein ratio) and balance (net protein utilization) characteristics of the biological value were determined in experiments on rats fed diets containing soybean proteins as the only source of proteins (10% of caloric value). The Dtr of the proteins under study was defined. All the evaluable proteins were found to be almost similar as regards the biological value. The Dtr of protein isolates was discovered to be higher as compared to that of soybean protein concentrates.