高酸值米糠油的活性白土与硅胶联合脱色工艺研究Bleaching of high acid value rice bran oil through activated clay combined with silica gel

Abstract

对高酸值米糠油的活性白土与硅胶联合脱色工艺进行研究。对酸值（KOH）为27 mg/g的米糠油进行先活性白土后硅胶脱色，以脱色率、谷维素含量和精炼率为考察指标，在单因素试验的基础上采用响应面试验优化活性白土与硅胶联合脱色条件。结果表明：活性白土脱色最优工艺条件为活性白土添加量25%、脱色时间30 min、脱色温度90 ℃；硅胶脱色最优工艺条件为硅胶添加量2.0%、脱色时间30 min、脱色温度82 ℃。在最优工艺条件下，活性白土脱色后，米糠油脱色率为79.15%，谷维素含量为2.14%，精炼率为90.05%；再经硅胶脱色后，米糠油脱色率为47%，谷维素含量为2.10%，精炼率为88.36%。经过活性白土与硅胶联合脱色后米糠油的色泽明显改善，色泽（25.4 mm罗维朋比色槽）由原油的Y35、R15降至Y5、R0.3。 The bleaching of high acid value rice bran oil through activated clay combined with silica gel was studied.The rice bran oil with acid value 27mgKOH/g was firstly bleached by activated clay then by silica gel. With the bleaching rate, oryzanol content and refining rate as indexes, response surface methodology was used to optimize the combined bleaching conditions based on single factor experiment. The results showed that the optimal bleaching conditions for activated clay were obtained as follows: activated clay dosage 2.5%,bleaching time 30 min and bleaching temperature 90 ℃. The optimal bleaching conditions for silica gel were obtained as follows: silica gel dosage 2.0%, bleaching time 30 min and bleaching temperature 82 ℃. Under the optimal conditions, the bleaching rate of rice bran oil was 79.15%, the content of oryzanol was 2.14%, and the refining rate was 90.05% after bleaching by activated clay,and the bleaching rate of rice bran oil was 47%, the content of oryzanol was 2.10%, and the refining rate was 88.36% after bleaching by silica gel. After combined bleaching of activated clay and silica gel, the color of the rice bran oil improved significantly from Y35,R15 of crude oil to Y5, R0.3 (254 mm Rovipon colourimetric bath).

Keywords

• 高酸值米糠油；活性白土脱色；硅胶脱色；联合脱色
• high acid value rice bran oil; activated clay bleaching; silica gel bleaching; combined bleaching