The Research And Application Of Rice Bran

Rice is consisted of rice husk,seed coat,the aleurone layer,endosperm and embryo,the brown rice is formed after hulling.Rice bran is a by-product of the brown rice milling,mainly consists of seed coat,aleurone layer,embryo and little endosperm,which is about 10% of the total weight of rice.An annual output of rice bran is about 12 million tons in China,but the effective utilization rate of rice bran is less than 20%,the waste is already serious,the deep development of rice bran resource is not wide enough at domestic and overseas,so the comprehensive utilization value needs to improve.This research is to explore the varying pattern of rice bran’s rancidity and then seek a method which can makei it store well.With stabilized rice bran as raw material,we explore the application of rice bran in the actual production of life.1、The main nutritional components of fresh rice bran.The result show that the total sugar,protein,reducing sugar,crude fiber,ash,phytic acid are 28.88%,14.51%,2.72%,6.30%,8.15% and 9.45% in fresh rice bran.The bioactive substances,such as oryzanol,polyphenols,flavonoids are 0.42%,0.64% and 0.29%.The crude fat content of rice bran is up to 22.34%,and the content of the oleic acid and linoleic acid is 74.93%,and the ratio is 1.17:1,so the rice bran oil is a typical type of linoleic acid-oleic acid oil;The total amino acid of defatted rice bran is 206.75 g/kg,the essential amino acid content is 60.39g/kg,and the amino acid composition is reasonable.2、The laws of rancidity and storage characteristics of rice bran.The result show that:(1)The AV value in illumination is slightly higher than in dark place.The oxidation stabilization period of POV and PAV were 0-15 d and 0-25 d respectively in illumination,and the enzyme activity is still higher than 20 mg/g in 60 d,significant higher than the rice bran keeping in dark place.(2)The highest AV value of rice bran in 16℃ and 30℃were 155.73 mg/g oil and 168.45 mg/g oil;The POV and PAV value increased to 149.2and 13.67 in 35 d rapidly under the condition of 16℃.The POV value is more than 50 and the PAV value is more than 20 in 25 d under the condition of 30℃.While the AV value reached 72.60 mg/g oil,the oxidative stability period of POV and PAV value were0-45 d and 0-40 d under the condition of 4℃.(3)The POV value of control group,VC group,VE group and BHT group were 66.34,27.12,15.64,15.03 mmol/kg in 55 d,so the antioxidants has advantages on oxidative rancidity.(4)The value of POV and PAV increased slowly after removing oxygen,but while the AV value and lipase activity can’t be inhibited effectively.3、The study of rice bran stabilization.Optimize the microwave-assisted sterilizing enzyme conditions using optimization response surface methodology.The optimal levels:initial moisture content 29.4%,109.4s treatment at a microwave power 619.45 W.Under optimized conditions,the average residual enzyme activity was 0.665%,the actual value is 0.662%,the relative deviation is 1.80%.Compared with processed by cooking and extrusion,the storage stability of rice bran after microwave treatment had obvious advantages.4、The comprehensive utilization of rice bran.Optimizing the formula of rice bran biscuit;Adopting the method of enzymolysis on the optimum process of extraction of rice bran protein;The solid-state fermentation method was used to improve the nutritional value of rice bran.The result are as follows:(1)The optimal formula of rice bran biscuit: PFR is 7:3,the amount of sugar added is 30%,rice bran oil is 45%,egg is 35%,baking soda is 0.9%.The sensory quality of the biscuit is better,and the physicochemical indexes are all in line with national standards.By the strengthening storage experiment,we predict that the shelf life of rice bran biscuit is about 8 month in 20℃.(2)The best technological conditions of enzymolysis: cellulase(0.5%)and amylase(1.5%)synchronously,the ratio of material to liquid is 1:6,p H is 5.5and the response time is 2 hours.Under this condition the protein extraction rate was73.87%.To obtain crude protein product,we use the spray drying method.The crude protein content is as high as 70%.(3)Mixed solid fermentation has the obvious advantages in improving the polypeptide,GABA content and reducing phytic acid content over single solid fermentation.Mixed fermentation of group F improved106.25% of polypeptide than control;The content of GABA is up to 13.72 mg/g rice bran in the mixed fermentation of group C;The mixed fermentation has the obvious advantages in reducing phytic acid,the reducing percentage of group C and group A was up to 42.44% and 35.19% respectively.But mixed fermentation has no significant advantage in the improving of free amino acid and reducing sugar content.