The Research On Extraction And Refining Process Of Rice Bran Oil

China is the largest rice-producing country in the world, the annual output is about190million tons. Rice bran is an important by-product of rice processing. Rice bran content calculated at7%, so annual rice bran production capacity is13.3million tons. The oil content of rice bran is up to20%, quite with soybean oil content. So, the rice bran oil is an important oil source.Rice bran oil as a new type of natural vegetable oils, contains many special active ingredients what is good for health and other fats without. Rice bran oil has the functions of improving immunity, lowering cholesterol, regulating blood fat, preventing arteriosclerosis and other functions, so its nutritional value exceed soybean oil, rapeseed oil and so on. Rice bran oil is increasingly subject to the attention and favor of consumers, because of its nutritional value and health care function.However, rice bran resource is distributed very scattered and wide, that is hard to get together in short time for oil production. In addition, rice bran has lipolytic enzyme, which has very high activity. So rice bran materials easily rancidity and deterioration, crude rice bran oil has relatively high acid value. And because many technical difficulties exist in rice bran oil extraction and refining process, so not easy to prepare high level edible bran oil. These factors are restricting the development of China’s industrialization of rice bran oil. The industrialization development of rice bran oil has great significance to China’s edible oil:(1) to improve the self-sufficiency rate of China’s edible vegetable oil, currently China’s edible vegetable oil relies on imports more than60%;(2) to increase the nutritional value of China’s rice bran oil, the current domestic market sales rice bran oil, which’s oryzanol basic all loss or destruction at refining process.So the research on preservation technology of rice bran, rice bran oil extraction and refining is very important. In this paper, the process of rice bran stabilization by microwave, solvent extraction process of rice bran oil with high concentration of oryzanol and the refining process of rice bran oil.In this study, the fresh rice bran as raw material, the goal is optimize the process of rice bran stabilization by microwave heating, study effects of the moisture content of the rice bran, microwave treatment power and microwave treatment time on the stabilization of rice bran microwave.Selecting10kinds of organic solvent to extract rice bran oil, then select high extraction rate and high rice bran oil oryzanol content solvent for the test of the ratio, and factors such as extraction temperature, solid-liquid ratio and extraction time were respectively analyzed in order to find out their impact on the rice bran oil yield and the oryzanol content of the oil, and orthogonal test be used to optimize the extraction process.At last, the research is focus on bleaching and deacidification steps of refining rice bran crude oil.Orthogonal experiment was employed to optimize best parameter of microwave stabilization process. The optimum conditions of microwave processing was180s of microwave processing time,22%of rice bran moisture content,800W of microwave power. Under the optimal condition, the residual activity of rice bran peroxidase was4.06%, and acid value was7.02mg KOH/g.The optimization results of solvent extraction process of rice bran oil with high concentration of oryzanol were:extraction solvent:isopropyl and Solvent-extracted oil No.6(1:1,v:v); extraction temperature:50℃; solid-liquid ratio:1:5; leaching time:60min. Under this condition, the extraction rate of rice bran oil was16.20%and the oryzanol content of rice bran oil was1.3739%.Rice bran oil refining process was:heat rice bran crude oil to40℃, add to the mass fraction of85%phosphoric acid, and the added amount is0.2%of the weight of oil, after thorough mixing of the two substances heat the solution to70℃, add to the soft water of the same temperature for hydration, and the added amount is6%of the heavy oil, then stand for3～8h after unglued30min, and then subjected to oil-water separation, atmospheric dehydration. Phosphorus content of degummed oil is decreased from642.5mg/Kg to23.9mg/Kg. The degummed oils cooling and crystallization in the refrigerator, the cooling temperature is4℃, the crystallization time is72h, filtration temperature is15℃. The dewaxed oil is heated to about120℃, then added activated clay (5%of oil weight) and activated carbon(5%of activated clay weight), decolorizing time is20min. Grease chrominance is R3.7Y33.0B1.0. Appling the method of mixed oil alkali refining twice to deacidification. The first alkali refining:NaOH concentration5%(W/V), oil to hexane ratio1:2, reaction temperature55℃, reaction time60min, acid value reduction4; the second alkali refining:NaOH concentration11%(W/V), reaction temperature60℃, reaction time 120min, oryzanol content is1.8262%, oil refining yield is83.70%.