| Rice bran oil(RBO) is called nutritious and sanitarian oil,because the composition of the fatty acid of RBO is reasonable and it contains a lot of Oleic acid, linoleic acid and other nutriment.Lipase could lead the oil hydrolyzed if the rice bran not passivated in time especially in the high temperature,which in order to increase the acid value of RBO.The traditional refining methods are not suit for RBO.Because it not only lead to the low refining rate(only 50%),but also destroys the oryzanol and depress the economic benefits.Seek for the best refining method is a difficult and hot issue of RBO refining.In order to resolve the problem,the pretreatment and deacidification technology of RBO was studied.The experiments investigation indicates:1.The optimum conditions of degumming of rice bran with high acid value were: citric acid 0.20%,water 3%,temperature 80℃,hydration time 25min.The content of phospholipid reduced to 19.58mg/kg.The optimum conditions of bleaching of rice bran with high acid value were:activated carbon accounted for 15%of mixed decolorant,decolorant 2.5%,bleaching temperature 90℃,bleaching time 20min.The decolorization rate was raised to 81.07%2.Compared five different kinds of catalyzers,the results showed that ZnO had the best catalysis activity.Esterification using ZnO,and the influence of glycerol dosage,catalyzer dosage,reaction temperature and reaction time were studied.The optimum conditions of esterification using ZnO were theoretical amount of glycerol, 0.1%(w/w) catalyzer dosage,reaction temperature 200℃.Under the optimum conditions the acid value dropped from 38.14 mgKOH/g to 2.92 mgKOH/g after reaction for 6h.3.The content of monoglyceride,diglyceride and triglyceride raise to 3.41%, 14.10%,76.35%from 2.40%,8.92%,66.47%after esterification.The content of oryzanol of rice bran oil only lost 24.59%after esterification.Through the determination of physical and chemical indicators,the indicators have reached the national standard.
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