Progress and future needs for research in soya protein utilization and nutrition

Although soya protein was clearly recognized as an essential part of the diet in the Orient centuries ago, its acceptance in the western world has been slow and recent. Progress in utilization has revolved around solving problems of flavor, nutrition and functionality, and has resulted in commercial development of flours and grits, concentrates, isolates, textured products, cereal-soya blends and beef-soya blends. Among the latter two developments, cereal-soya blends established the principle of using soya to increase protein content and quality of cereal diets consumed in many countries, and beef-soya blends demonstrated the usefulness of soya in extending expensive meat supplies. Governmental actions such as approval of soya in school lunches and in military diets in the U.S. have also contributed to progress in utilizing soya protein in foods. Future research needed to increase food uses of soya protein includes: further improvement in flavor, greater versatility in functional properties, development of new foods rather than simulation of traditional items, and elaboration of adequate methods for determining soya proteins in regulated products. Highlights in soya protein nutrition research include: discovery of the need for moist heat treatment to develop maximal nutritive value; establishment of methionine as the first limiting amino acid; isolation and characterization of trypsin inhibitors; determination that trypsin inhibitor retards growth and causes pancreatic hypertrophy; discovery of negative feedback control of pancreatic enzyme secretion; and demonstration of apparent adequacy of soya proteins in meeting protein requirements of young children and adults. Further nutritional research is needed in the following areas: long-term studies with humans to determine protein quality as well as possible needs for fortification with vitamins and minerals; establishment of need or lack of need for supplementation with methionine; mechanism of action trypsin inhibitors when ingested from soya and other sources; and development of rapid methods for measuring protein quality.