Effect of germination of legume seeds on chemical composition and on protein and energy utilization in rats

Chemical composition of soybeans, lupin seeds and black beans, and protein utilization and energy digestibility of soybeans and lupin seeds determined in a rat model, were compared before and after a 48-h germination. Black beans had a much higher starch content and lower levels of low-molecular-weight (LMW) sugars than soybeans and lupin seeds. Lupin seeds had about twice as much non-starch polysaccharides than the other legumes and higher insoluble dietary fiber. Soluble dietary fiber represented over one third of total dietary fiber in all legumes. After germination, LMW α-galactosides decreased in all seeds, particularly in lupins. Sucrose levels increased in lupins and black beans but decreased in soybeans. Biological indices were significantly higher in lupin seeds than in soybeans. Germination produced a small increase in protein utilization in both legumes. These results indicate that the main advantage of a 48-h germination of legume seeds is the reduction in the α-galactosides.