Genetic variability and effect of heat treatment on trypsin inhibitor content in soybean [Glycine max (L.) Merrill.]

Kunitz trypsin inhibitor (KTI), a major anti-nutritional factor present in soybean seed, is a major bottleneck in industrial use of soybean and public acceptance of soybean food products. Biochemical screening for trypsin inhibitor content was carried out in 145 genotypes of soybean comprising exotic collections and released varieties. The trypsin inhibitor content ranged from 14.15 to 186.27 mg g⁻¹ of seed meal. Lowest level of trypsin inhibitor content was observed in genotype PI542044, (14.15 mg g-1 seed meal). Popular Indian soybean varieties viz., JS335, JS9305, NRC37, NRC7, PK1225, DS9712, JS9752, and DS9814 contained higher level of trypsin inhibitor. Heat treatment was able to reduce the TI content but to certain level leaving about 20% residual activity. The study indicated the need for other ways to create genotypes with reduced KTI for use in breeding program.