Multi-step Extraction And Separation Of The Main Components From Full-fat Rice Bran

Getting crude oil and using defatted rice bran as feed ingredient were the commonutilization method of full-fat rice bran. In the scheme, only the lipid component was utilized,the other components were ignored, so it caused secondary waste. In this paper, the effectiveextraction and separation of the main components from full-fat rice bran were studied, and anew way to make full use of full-fat rice bran was explored.First of all, the method of acid immersion was employed in extracting phytic acid andsynchronously inactivating the lipase in full-fat rice bran. The impact of acid concentration,temperature, time and solid to liquid ratio on phytic acid yield and residual lipase activitywere studied. The best immersion conditions were obtained by orthogonal and verificationexperiment as follows: acid concentration1.2%, temperature50℃, time4h and solid toliquid ration1:10. Under the conditions, the extraction rate of phytic acid was82.3%; thelipase activity was reduced by93.6%compared with raw material. In the process, most ofaleuronic cell wall structure was destroyed,91%total sugar,86.8%ash was leached, and themain components were retained; free fatty acids were increased from6.3mg/g to16.5mg/g,peroxide value and fatty acid composition didn’t change. Crude calcium phytate was obtainedby Ca(OH)2-NaOH two-step precipitate. Through acid dissolution, filtration, bleaching,alkaline precipitation, the refined calcium phytate which meet the quality requirements ofedible calcium phytate was obtained.Secondly, lipid was extracted. Three oil extraction programs (enzyme-assisted aqueousextraction, dry solvent extraction, wet solvent extraction) were compared. Cellulase andAlcalase extracting step by step could get the best result in enzyme-assisted aqueousextraction; in dry solvent extraction, the scheme of freeze-dried was the best; in wet solventextraction, the result of high shear devices were better, the solvent which mixed by hexaneand isopropanol could get the best result when colloid was selected as the device.Take intoaccount lipid extraction rate, lipid quality and cost, wet solvent extraction was selected. Wetsolvent extraction conditions were optimized and the optimum process conditions wereresidue: isopropanol (DW/V)=1:4, residue: hexane (DW/V)=1:4, rubber grinding time5min. Under the condition, the oil extraction rate was91.4%. Crude oil was obtained byvacuum desolventizing and centrifugal, the yield was15.1%, and its quality reached thenational standard.Once again, protein was extracted. Alkaline and enzymatic extractions of protein werecompared. Taking into account the protein extraction yield and purity, acid protease was usedto extract protein. The protein extraction conditions were optimized and the optimumconditions were enzyme amount4000U/g, temperature50℃, pH3.0, time4h, solid to liquidration1:8. Under the condition, protein extraction rate was52.3%, the purity was51.6%. Theobtained rice bran protein was composed mainly of small peptides and amino acids, and theprotein was rich in glutamate, histamine and lack of lysine, threonine.Finally, dietary fiber was extracted. Dietary fiber was obtained by enzymatic removal ofstarch; the conditions of remove starch by high temperature amylase were optimized by usingdietary fiber purity as the indicator. Under temperature50℃, pH5.6, the optimum conditionswere enzyme amount0.5%, time40min, solid to liquid ration (DW/V)=1:6. Under thecondition, dietary fiber extraction rate was61.2%, the purity was75.9%. Dietary fiber product was prepared by ultrafine grinding through ball milling, when the milling time was9min, thecontent of soluble dietary fiber was5.3%, and it reached the second quality standard ofsoybean dietary fiber powder.The research achievement was compared with the literature, patents. Overall, theresearch achievement was quite when compared with the extraction and separation ofindividual component. When compared with the extraction and separation ofmuti-components, the idea and methods of the process were rational and the search achieved agood result.