Nutritional evaluation of soya beans (glycine max): Nitrogen balance and fractionation studies

✍ Scribed by George Grant; Norma H. McKenzie; William B. Watt; James C. Stewart; Patricia M. Dorward; Arpad Pusztai

• Book ID: 102921326
• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 617 KB
• Volume: 37
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/jsfa.2740371008

✦ Synopsis

The poor nutritional performance of rats fed raw soya-bean-containing diets appeared to be due to reduced apparent digestion and absorption of dietary protein, coupled to changes in systemic metabolism leading to a poor overall nitrogen balance. Aqueous heat treatment greatly reduced but did not eliminate the antinutritional effect. Heat treatment with aqueous ethanol was more effective. The whey protein (pH 4.8 soluble extract) fraction contained the bulk of the trypsin inhibitor and haemagglutination activity and gave the poorest net protein utilisation value. However, an eight-fold increase in trypsin inhibitor content did not significantly effect apparent nitrogen digestibility. Therefore inhibition of gut proteolytic enzyme activity in vivo by soya bean trypsin inhibitors did not account fully for the poor nutritional performance. The problems elicited by soya bean are not transitory and thus there was a cumulative deterioration in overall performance for 16 weeks as a result of continuous exposure to soya bean.