The Development And Utilization Of Rice Bran Oil And Protein

In order to make full use of bran resources, the methods and processes for thepreparation of rice bran oil rich in oryzanol, rice bran protein and polypeptides was studied.Firstly, the optimum conditions of rice bran oil extraction using fresh rice bran as rawmaterial were determined. With physical refining process designed, process flow diagramdrew, and key process parameters of the expansion of production set, bran oil rich inoryzanol was obtained. Secondly, solvent extraction defatted rice bran at low temperaturewere used as raw material for preparing rice bran protein, and the optimal processingconditions of rice bran protein prepared by enzyme and ultrasonic assisted alkali-solutionand acid-isolation extraction were determined though orthogonal experiment based onsingle factor experiments. The protein content of rice bran protein product was improvedwith the treatment of saccharifying enzyme. And the effect of enzyme treatment times onprotein yield and protein content were analyzed. Protein got from the heat-stabilizeddefatted rice bran was compared with that obtained from defatted rice bran at lowtemperature to find out the causes of differences. At last, rice bran polypeptides were madeusing two-enzyme method in order to improve the functional properties of the rice branprotein products extracted from heat-stabilized rice bran meal. The main conclusions wereas follows：1．Fresh rice bran contains about20%of oil, and it is suitble for the extraction of ricebran oil. It was also identified the optimum extraction conditions of rice bran oil that areeaching time of240minutes, moisture of5%, ratio of solid to liquid of1:6, temperature of50℃. And under the conditions, we got the crude rice bran oil with oryzanol content of13.7mg/g and acid value of31.16mg KOH/g. Physical refining can effectively reduce theacid value, and oryzanol could be reserved at the same time. The results showed that theretention rate could reach86%, acid value could be reduced to2.0mg KOH/g, and therefined oil could reach the standard of grade four.2．The optimum conditions of rice bran protein extraction using enzyme and ultrasonicassisted alkali-solution and acid-isolation extraction were as follows: extractiontemperature was50℃, pH value was10.5, extraction time was100minutes, ratio of solidto liquid was1/10, and ultrasonic power was220W. As a result, the extraction rate reached57.6%.3．The protein content of products could be significantly increased with the treatmentof saccharifying enzyme. And the protein content of rice bran protein could be improved from60%to82%under the optimum conditions: enzymolysis temperature60℃, pH4.5,enzymatic hydrolysis time90minutes, the amount of enzyme0.3%, and ratio of liquid tosolid3:1.4．Protein extraction rate and protein content of protein product extracted fromheat-stabilized defatted rice bran were all lower than that from low temperature defattedrice bran. In addition, protein solubility of the former was obviously lower than the latter.The fundamental cause of such differences lay in the changes of amino acid compositiontand protein spatial structure.5．The water solubility of rice bran polypeptides product was good. And thepolypeptides were rich in essential amino acids. It can also make a balance with animalprotein for its abundant lysine and methionine. The optimum conditions for Flavourzymetreatment was: temperature50℃, pH6, reaction time60minutes, and0.5%of enzyme.Through single factor experiments and the regressive rotation design, the optimumenzymolysis conditions of Alcalase were determined as follows: temperature55℃, pH9.6,0.3%of enzyme,and enzyme time80minutes.