Effect Of Ingredients Changes Of Se-Enrichment Germinating Soybean On Processing Properties

After immersed in 10 mg/L Na2SeO3 solution 6h, soybean was germinated 96h at optimal conditions. Selenium (Se) content and changes of active materials in soybean at different germination time were studied. The effect of Se on soybean protein gel properties and other functional properties were investigated. According to research results, it was found that SPI separated from sprouting 24h soy owned the best functional properties, and then the SPI was added into flour to bake bread in the paper. The results were as follows:Selenium enrichment and changes of mainly active materials during soybean sprouting was studied. The results showed that total Selenium (T-Se) and organic Selenium (O-Se) contents were increased. Contents of T-Se and O-Se reached the max value of 4.60μg/g and 2.05μg/g after soybean sprouted 96h, respectively, and Se biotransformation rate was improved at the same time. Crude protein content in sprouting soybean increased from 38.12% to 40.75% at sprouted 96h. Some active materials in sprouting soybean were increased, such as soy isoflavone content from 0.38mg/g to 0.67 mg/g, GAB A content from 0.22mg/g to 0.48 mg/g, and Vitamin C content increased by 15.79%. Se-enriched soybean had a higher content of crude protein and GABA than the control, but Se-enrichment had no effect on contents of soy isoflavone and VC. Glutathione peroxidase activity in sprouting soybean reached the peak at germination time of 24h. Se-enriched soybean had a higher activity of glutathione peroxidase than the control.After added gluconolactone (GDL), soybean protein gels were analyzed by Texture Analyzer, and impacts of Se-enrichment and germination on soybean gel property were investigated. The results showed that the hardness of soybean gel and SPI gel decreased rapidly from 25.25g to 10.77g and from 27.73g to 13.37g respectively during 48h germination. Water holding capacity (WHC) of soybean gel and SPI gel decreased from 61.42% to 51.55% and from 62.64% to 55.54% respectively. Changes of SPI during soybean germination were discussed by SDS-PAGE mapping. The results showed that β-7S subunit and B-11S subunit were relatively stable, while a’-7S, a-7S, A3-11S and A-11S subunits were easily hydrolyzed by intra-proteases. At the same germination time, the protein bands of Se-enriched soybean were similar with control. It showed that enriched selenium had a little effect on soybean proteins and its’ gel property.The functional properties of Se-enriched SPI were changed during soybean sprouting. Change trend on solubility and water binding capacity of SPI was increasing firstly and then decreasing. Protein dispensability index (PDI) of SPI separated from 24h sprouting soybean was the maximum at 70.70%, and Se-enrichment had less effect on the solubility and water absorption of SPI. The oil absorption of SPI kept stable during soybean germination, but oil absorption of Se-enriched SPI was higher than the control. Change tendency on emulsifying property and foaming property of SPI were similar as solubility, the best value of emulsifying property and foaming property was determined at 0.36 and 92.0% respectively when soybean sprouted 24h, and Se-enrichment could enhance the emulsifying property of SPI. In one word, the best functional property of SPI was determined when soybean was germinated 24h. The correlation analysis showed that there was significant positive correlation between SPI solubility and water binding capacity (r=0.862**); the solubility had positive correlations with foaming properties (r=0.774*) and emulsifying properties (r=0.887*).Se-enriched soybean and SPI separated from sprouting 24h soybean had been added in flour and were baked bread. It was showed that water content, scent and taste of bread added Se-enriched soybean power were improved, aging speed of bread were delayed, and bread crust became brown color for Millard reaction. The bread which has the highest of sensory evaluation score was baked by flour added 2.0% sprouted soybean power. Flour added 6.0% sprouted soybean power brought beany flavor and bad taste to bread. After added sprouted soybean power or SPI, content of wet gluten and dry gluten in flour decreased, while dough formation time and dough stabilizing time were cut. When added 2.0% sprouted soybean power or SPI in flour, dough owned the optimal farinograph property and rheological property. Because effect of SPI on bread properties was similar as sprouted soybean power, adding sprouted soybean power in flour could keep nutrition value, but also was economical.