Effects of soybean (Glycine max) germination on biologically active components, nutritional values of seeds, and biological characteristics in rats.

We briefly reviewed the effects of soybean germination on biologically active components, nutritive value of seed and biological characteristics in rats. The purpose of this review is to evaluate the effects of soybean germination on nutritional values of seeds and the potential importance for the use of germinated soybeans, from a contemporary conception, in food preparation as well as on soybean possible influence in optimal health. Germination induced a substantial increase in the content of saponin, oestrogenic compounds and almost all phytosterols, particularly beta-sitosterol of seeds. Lecithin content increased slightly and gradually during germination process. Lipase and alpha-galactosidase activities increased whereas lipoxygenase activities reduced after a short period of germination (< or = 72 h). Therefore, the substantial odour and flavour scores of germinated soybean flour were improved. Germinated seeds were also beneficial to heat penetration, their thermolabile antinutritional factors were easier to inhibit than those of dry beans, also the seeds did not require a long cooking time to be palatable. Duration of the germination process greatly influenced the nutritional value and palatability of seeds and biological characteristics in rats. In rat bioassay, one-day germination of soybeans induced a significant increase of daily body weight gain, daily protein intake in rats and protein efficiency ratio (PER) of seed meal. Palatability of seeds was also improved whereas a 5-day germination resulted in a decrease of PER of seed meal (less than the value of unheated seeds) and induced thyroid enlargement in rats. A vapour thermal treatment (100 degrees C, 20 min) eliminated thyroid-active agents and improved PER of seed meal, food intake and final weight of rats. Well prepared germinated soybeans can be used as a good alternate to animal proteins for more balanced nutritional diet. Development of food products from germinated soybean may be another way to further increase the versatility and utility of soybeans for both developing and industrialized countries, as germination induced the modification of certain specific biologically active components, palatability and nutritive value of seeds.