| Rice bran is a by-product of rice processing industry, and its compostion depends on the processing degree of rice. The main components of rice bran are protein, fiber, ash, water and rice bran oil (RBO), etc. Usually, rice bran contains 16-25% of RBO, which can be refined as edible oil or used to produce bio-diesel. a substitute fuel for fossil diesel. Moreover, rice bran also contains a certain beneficial components with biological activity, such as oryzanol, sitosterol and tocopherol. in which oryzanol takes about 0.3-0.5%. As China hold one third of the annual rice production of the world, it produces nearly 1,000 tons of rice bran resources every year. However, the presence of lipases in rice bran easily leads the rancidity and deterioration of rice bran. In China, only 10% of the rice bran is utilized and most of the rest are used as animal feed or agricultural waste. It has not been fully utilized and caused environmental problems. Therefore, looking for a reasonable strategy to use and process rice bran will be of great significant.Recently, particular attention has been paid to bio-diesel. due to the energy crisis and environmental degradation, because it is a renewable, environmentally friendly, non-toxic and biodegrable "green energy". With similar combustion characteristics to the fossil diesel, bio-diesel is a promising alternative fuel. So far. most of bio-diesel is produced by esterification or transesterification reactions using vegetable oil or animal fat as raw materials. However, the cost of these raw materials usually accounts for 75% of the total cost of bio-diesel, which limited the development of bio-diesel industry. Therefore, it is crucial to find a plentiful, cheap and stable raw material.The content of oryzanol in rice bran is about 0.3-0.5%, and about 0.9-2.9% in rice bran oil. More and more attention has been paid on oryzanol. due to its special physiological functions on the hunman body such as analgesic. anti-bacterial. anti-inflammation, antioxidant, anti-free radical and anti-ultraviolet, etc. Therefore. extraction of oryzanol is of great significance.Therefore, we designed a process of in-situ preparation of fatty acid methyl ester (FAME) and simultaneously extraction of oryzanol. We used low quality rice bran as raw material and cyclohexane. anhydrous methanol and petroleum ether as solvent to investigate the relative parameters.Firstly, we examined the parameters of rice bran oil extraction experiments, by using rice bran as raw material and cyclohexane. methanol. petroleum ether, cyclohexane/anhydrous methanol and petroleum ether/anhydrous methanol as solvents. We found that the introduction of an appropriate amount of non-polar solvent was favorable to improve the extraction efficiency of rice bran oil. Conclusion: the best oil extraction rate of 18.72% could achieve when 50 g of rice bran and 220ml of azeotropic cyclohexane/methanol (139ml/81ml) were used after 3.5 h of reaction.Then, we investigated experimental conditions of in-situ production of bio-diesel in the third chapter. Conclusion:Esterification rate of 95.16% could achieve by using 0.5g of concentrated sulfuric acid as catalyst, and transesterification rate of 87.89% could further achieve by using 0.25g of sodium hydroxide as catalyst. The ester production yield was about 16.7%.Finally, in the fourth chapter, we investigated parameters of oryzanol extraction from oil phase. Conclusion:1. Using alkaline methanol lotion with 0.45g NaOH and 80% alcohol. approximately 82% of the oryzanol could be transferred from oil phase to methanol solution; 2. Extraction rate of 41.2% could achieve when 150ml (3 times the mass of raw material) of cyclohexane extraction agent was further applied to extract oryzanol from methanol solution with pH value of 8-9.The process of in-situ preparation of FAME and simultaneously extraction of oryzanol from rice bran is simple, solvent recyclable and pollution-free. The designed strategy can not only improve the added value of rice bran, but also has great significance on agricultural production and living standard improvement of famers. |
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