Effect Of Ingredients Changes Of Bean Sprouts On Processing Properties

Soybean has many good advantages, such as high nutritional value and betterfunctional properties. However, it must be processed before it can be eat becausesoybean owns hard structure, and some anti-nutritional factors. After appropriategermination, soybean nutritional value can be improved, but also the processingproperties of soybean are improved. So germination is a good processing method forsoybean and should be promoted.There are many researches focusing on changes of soy nutrition and processingtechnology of bean sprouts. However, the impact of ingredient changes of soy sproutson processing performance is rarely studied, and it restricts germination soyprocessing. In the paper, the research focused on changes of the main components,soy protein components and oxidoreductase activity after soy germinating. Effect ofchanges of soybean protein isolate （SPI） on its functional properties was discussedand the results would provide a theoretical basis for promoting germination soy. Themain results were:The basic components changed during soy germination, the protein contentreduced slightly after germination and minimum of34.0%at3cm soy sprouts.Amino nitrogen content continued to increase during soy germination, its contentincreased to10.3%at6cm soy sprouts. Soluble sugar content decreased gradually, itscontent reduced to1.43%at6cm soy sprouts. Fat content had slight reduction,unsaturated fatty acid reduced while saturated fatty acid increased. GABA content was80μg/g after soaking, significantly higher than the original soybean20μg/g.Isoflavones content increased, reached a maximum13μg/g at5cm soy sprouts.SPI was degraded during soy was germinating. SDS-PAGE of SPI showed thatSPI was degraded after germination,11S globulin had less change than7S, and7Sglobulin was more susceptible to hydrolysis by the endogenous proteinase.Gel strength of germinating soy was different with soy. The gel strength of soyand SPI was the strongest at1cm soy sprouts, the effects of coagulants are:GDL>CaSO₄>CaCl₂>MgSO₄. The changes of SPI, especially the changes of7S and11S affected the formation of network structure between the protein molecules, thusaffected the gel strength.The functional properties of SPI changed during soy were germinating. Thefunctional properties of germinating SPI such as solubility, water absorption, foamingand emulsifying were improved, of which the1cm bean sprouts were best. This showed that germination could improve the functional properties of soy protein in acertain extent.The oxidoreductases changed during soy were germinating. The activity of LOXwas increased, the strongest activity was at2cm soy sprouts, reached76933U/mL.Theactivity of peroxidase was gradually reduced, and it was38328U/mL at0cm soysprouts, while it was only13353U/mL at5cm soy sprouts. The peroxide value ofsoybean, which was measured by GB/T5538-2005, was decreased after germination.