Research On Bacillus Subtilis Solid-Fermentation Of Rice Bran And Its Function Of Triglyceride-Lowering

Rice bran is a cheap but nutritious by-products from rice. It contains alcohol y-oryzanol, nicotinic acid, a-tocopherol, and other functional ingredients. It has the function of lowering blood fat, blood sugar, prevention of cardiovascular diseases, cancer prevention, weight loss, antifatigue, beauty, anti-inflammatory sterilization and so on. China is big country of production of rice bran, the utilization of rice bran is stuck at the primary products of feed, rice bran oil, was limited the potential value of the intensive utilization of rice bran. Therefore, the more comprehensive should be utilized of rice bran resources, rice bran functional food will developmenting as processing direction of rice bran especially.In this paper, Bacillus subtilis XZI-125 of high-yield of plasmin was used in solid-state fermentation of rice bran. Besides, the rice bran medium was optimized by the method of uniform design, based on which the shake flask cultures and the shallow dish culture were optimized, and the change of functional components before and after the fermentation were measured. On this basis, the function of lowering triglyceride of the original and fermented rice bran was valued by animal experiments, which provides a theoretical basis for the development and application of rice bran. The main results are as follows:1.Optimization of solid-state fermentation media and culture conditions. Through the single factor experiment with plasmin live and y-oryzanol content as indicators, the different carbon source, nitrogen source and inorganic salt, fermentation accelerants of rice bran solid medium were screened, thus determing the added ingredients of the rice bran solid state fermentation medium. By exploiting the ten factors and varying levels uniform design, the regression equation was achieved. And the optimum dosage of each additive was further predicted, after which verification test was conducted. The solid state fermentation medium components were finalized:the water ratio 1:0.6, peptone 6.0%, soluble starch 5.43%, Tween 200.35%, CaCl20.642%.The culture conditions for rice bran solid state fermentation medium were determined by single factor and three-factor two levels orthogonal test:the temperature was 37℃, inoculation was 9%, and fermentation time was 96 h. The final plasmin live of the fermented rice bran was 3885.09±22.83 U/g, and γ-oryzanol content was 4.74±0.07 mg/g.2.Skilling up with the platter and the changes of the functional components. Using the plasmin live and y-oryzanol content of fermented rice bran as indicators, the culture conditions were optimized through single factor and orthogonal experiment as:each panel mounted 300 g rice bran, the water ratio of the medium is 1:0.8, inoculated the seed solution content is 11%, then water was added to the medium at the ratio of 1:0.4 after 48h of fermentation before well mixed. And the fermentation process was ended at 72 h. The final plasmin live of the fermented rice bran was 3388.25 U/g and y-oryzanol content was 4.51 mg/g.Then the y-oryzanol, nicotinic acid, polysaccharides, a-tocopherol, and total dietary fiber content before and after fermentation were analyzed. The results showed that the content of y-oryzanol improved 1.63 times compared to the original rice bran, the VE content of the original bran is only 0.023 mg/g, after fermentation it incresed to 0.040 mg/g, increased 1.74 times; the content of dietary fiber rised from 0.251 mg/g to 0.603 mg/g, increased 2.41 times;the content of niacin from 1.25 mg/g up to 3.01 mg/g, increased 2.41 times;and the polysaccharide content did not change significantly when compared with that before fermentation. So the functional components of fermented rice bran was better than the raw rice bran.3.Animal studies of the triglyceride-lowering function of rice bran. The mixed model of hyperlipidemia rats was built by feeding rats high cholesterol diet. Feeding rats raw rice bran and fermentation rice bran respectively, and determining the serum total cholesterol (TC) test, triglyceride (TG), high density lipoprotein (HDL-C), low density lipoprotein (LDL-C) in these rats. The results showed that the improved rice bran had significantly reduced triglycerides for mixed hyperlipidemia rats. And high, medium and low dose groups of fermented rice bran reduced overall triglycerides by 17.6%,16.0%, 15.1% respectively. Even more the improved rice bran behaved significantly better than the original rice bran, with a statistically significant difference to the model group, which implied that the improved rice bran had a function of lowering triglycerides in rats.