SOYBEAN WHEY PROTEINS-RECOVERY AND AMINO ACID ANALYSIS

SUMMARY– About 14 million Ib of soybean whey protein of high biological value is disposed of as waste based on estimated production figures for soybean concentrates and isolates. An estimated 5–7% annual increase in consumption poses serious waste disposal problems and alternates should be sought. By simulated commercial procedures, yield and protein content of soybean whey were determined. Whey solids account for 2–28% of original nitrogen in dehulled, defatted flakes. Whole whey protein was prepared by dialysis, and whey was also fractionated by heating into heat-coagulable and supernatant proteins. Whole whey protein has a good balance of essential amino acids when compared with a system followed by the Food and Agricultural Organization of United Nations based on hen's egg protein. Heat-coagulable and supernatant proteins varied greatly: heat-coagulable fractions had 42% of the sulfur amino acid content but 181% of the tryptophan content of hen's egg protein; supernatant protein had 142% of the sulfur amino acid content but only about 60% of the isolevcine, valine, leucine and tryptophan content of hen's egg protein. All three whey protein fractions would be suitable for addition to feeds.