Optimization Of Refining Process Of Rice Bran Oil With High Acid Value

Rice bran oil is consider as high nutrition and its fatty acid composition is reasonable. Unsaturated fatty acids is as high as 80%, more than 42% in which is oleic acid and 38% is linoleic acid. This proportion of fatty acid is close to the recommendation of World Health Organization(oleic acid : linoleic acid = 1:1). In addition, a variety of functional substances in rice bran oil could account for 4.2%, including oryzanol, vitamin E, sterol, etc. However, now the development and utilization of rice bran oil meeting some limitation due to the relative high acid value and wax content. According to the present reports, refining yield of rice bran oil is lower than other oils. Moreover, the existing oil refining process would easily destroy the functional substa nces in rice bran oil, such as oryzanol. Therefore, it is urgent to look for a novel refining process, which could not only reduce the acid value and wax content, but also remain the mass of functional components(oryzanol, vitamin E and sterols, etc).In this study, rice bran oil with high acid value has been used as raw material, to optimize the progress to degum and dewax at the same time, as well as remain the functional components. The results are listed as following:(1) The degumming process of rice bran oil with high acid value was optimized through single factor experiment and orthogonal experiment analysis. The optimal parameters were obtained combined with the actual operability: rice bran oil with high acid value 100 mL, water content 3 mL, citric acid concentration 50 g/ml, degumming time of 25 min, acid 0.25 mL, degumming temperature 60℃. Under this condition, degumming yield of rice bran oil with high acid value reached 95.23%.(2) By using rice bran oil with high acid value as raw material, ac id removing, dewaxing, oryzanol content and yield were considered to the effect of solvent, extraction times, degumming or not on the refining. Results indicated that the dewaxing yield is the optimal that using 95% ethanol as solvent and extracting severa l times and no degumming.As well as, lecithin in the raw rice bran oil could promote the acid remove and dewaxing.(3) Optimal refining process was determined based on single factor experiment and orthogonal experiment acid by using rice bran oil with high acid value as a raw material. the optimum parameters are: lecithin content- 0.15% of the volume of the solvent, solid- liquid ratio- 1:3, extraction time- 40 min, extraction temperature- 60 ℃ and extraction times- 4 times. Under these parameter, the acid removing rate was 99.45%, dewaxing rate was 99.86%, remaining rate of oryzanol was 87.88%, remaining rate of vitamin E was 95.15% and remaining rate of sterol retention was 97.64%.Results above indicated that refining process optimized in this work co uld remove the gum, acid and wax in the rice bran oil with high acid value at the same time, and also remain the mass of functional components.