Chemical and nutritional changes in soybean during germination

Germination of soybeans for 6 days depressed the trypsin inhibitor activity by 32%. Oil content, acid value, iodine value and total unsaturated fatty acids of soybean oil decreased while peroxide value and total saturated fatty acids pronouncedly increased. Percentage of palmitic and linoleic fatty acids were highly affected during germination. Analysis of the hydrocarbon and sterol classes revealed n-tricosane and β-sitosterol to be, respectively, the major components. Marked changes in both hydrocarbon and sterol constituents occurred upon germination. Different periods of soybean germination increased non-protein nitrogen and decreased reducing sugars. However, total ash content decreased due to soaking; thereafter it was constant for the rest of the germination period. Different amino acid components increased due to germination when compared with their content in dry seeds. The protein solubility of germinated soybean was higher in H₂O, 5% NaCl and 0·02m NaOH than it was in ungerminated seeds. Water and oil absorption, emulsification and foaming capacities of soybean were increased after germination. A marked improvement in digestibility by pepsin was noticed while tryptic digestibility was still low (38%). PAGE patterns showed drastic changes in both low and high molecular weight protein fractions due to germination.