Effect of maturity and processing on the trypsin inhibitor and oligosaccharides of soybeans

ABSTRACT Immature soybean seeds are used as human food, but they contain antinutritional factors. The trypsin inhibitory activity (TIA) increased slightly in soybean cv Beeson‐80 but remained unchanged in cv Pella, as maturation advanced. Steaming or cooking for 20 min, as commonly practiced, fully eliminated TIA in immature seeds. Soaking (24 hr) plus cooking (20 min) was necessary for the complete disappearance of TIA in mature seeds. Sucrose, raffinose and stachyose concentrations increased significantly with maturation. Steamed or cooked immature seeds contained considerably smaller quantities of raffinose and stachyose, sugars associated with flatulence, than similarly treated mature seeds.