Using Bacillus Subtilis XZI125to Improve Functional Components And Nutritional Value Of Rice Bran

Rice bran contains a large amount of protein, fat, crude fiber and ash (mainly phytate), in which protein and amino acids relatively completed, as well as mainly47%unsaturated fatty acids. In addition, rice bran is rich in vitamins, minerals, polysaccharide, tocopherol, γ-oryzanol,28-octacosanol, squalene, ceramide and other physiological functional components. Even though China’s annual output of rice bran reached10,000,000tons, the utilization rate is very low, expect for approximately10%～15%of rice bran for extracting rice bran oil or extracting of calcium phytate, and other products were used as animal feed. From the composition of rice bran, it can be used as food, health products, medicine and raw materials of chemical industry, so it has a huge potential for development and utilization.In this research, we fermented rice bran with high-producing fibrinolytic enzyme Bacillus subtilis XZI125. And improved the fermentation conditions of the rice bran in order to optimize the production of fibrinolytic enzyme, and reduce the content of phytic acid. We improved the overall nutrition as well as medical benefits of rice bran to exert better usage in the future. The main results are as follows:1. Reducing the content of phytic acid in rice bran and enhancing activity of fibrinolytic enzyme by liquid fermentation. Results show that, fermentation time, fermentation temperature and sodium chloride plays a significant effect on the reduction of phytic acid and the activity of fibrinolytic enzyme. The optimized the medium and cultured conditions:temperature33℃and the rotation speed180r/min for48h, plus Tween-800.2%, yeast extract0.1%, malt sugar1%, sodium chloride0.1%, inoculation1%, liquid volume100mL/250mL erlenmeyer flask, rice bran14%, natural pH. Under these conditions, the activity of fibrinolytic enzyme reached831.79±144.98IU/mL, the reduction rate of phytic acid is62%.2. Improving the activity of fibrinolytic enzyme by solid state fermentation. Results show that the water content of fermentation medium, fermentation time, fermentation temperature, and sodium chloride have a greater impact on the activity of fibrinolytic enzyme. The best fermentation conditions are:material loading15g in the250mL erlenmeyer flask, inoculation amount1%,30℃,72h, liquid solid ratio is0.6, NaCl0.01g. The fermentation results obtained fibrinolytic enzyme activity3317.46±259.91IU/g rice bran(wet weight).3. Research on the effect of fermentation on the nutritional value and function of rice bran. Determination of nutritional value of rice bran, showed that after the solid state/liquid fermentation the total phenolic content increased by a factor of3.4/2.5; flavonoid content increased by a factor of1.5/1.1; ferulic acid content increased by a factor of0.98/0.6; VE content increased by a factor of1.2/1.5; SDF content increased by a factor of2.5/1.2; γ-oryzanol content increased by a factor of2/2.8; the content of VB1increased by a factor of3.5/7.2; the content of nicotinic acid increased by a factor of36/47; VB6content increased by a factor of2.5/3.5. The nutritional value of fermented rice bran is better than raw rice bran.The hypolipidemic effect of the rice bran was evaluated by significance analysis of the results. Rice bran and fermented rice bran showed significant effects on lowering blood lipid level, and fermented rice bran was better than raw rice bran.