Changes in the quality of soybean during storage. Part 1—Effect of storage on some physico-chemical properties of soybean

Abstract Soybean ( Glycine max ) seeds of the Bragg variety stored in Jute bags under ambient conditions for 1, 2, 3 and 9 years were analysed for some physico-chemical characteristics to investigate the effect of storage period. The kernel weight and density decreased whereas hardness increased. The colour changed from creamy yellow to brown and grains stored for three years were slightly infested whereas those stored for nine years were heavily infested with insects. Among chemical characteristics, moisture content, fat, water-soluble nitrogen (WSN), nitrogen solubility index (NSI), sugars, trypsin inhibitor activity, available lysine, pigment and lipoxygenase activity of seeds decreased during storage whereas non-protein nitrogen (NPN), extent of browning, free fatty acid (FFA) content and peroxide value increased. Ash content and phytic phosphorus first increased and thereafter decreased with increasing storage period.