几种脱色剂对菜籽油脱色效果的研究

Bleaching effects of several decolorants on rapeseed oil

以菜籽油的色泽红值和叶绿素含量为考察指标,比较了凹凸棒土、活性白土、活性炭和双氧水4种脱色剂对菜籽油在中低温(40~80℃)下的脱色效果,同时考察了凹凸棒土与活性炭、活性白土与活性炭组成的复合吸附脱色剂对菜籽油的脱色效果。结果表明:活性炭在较低添加量条件下可以获得与凹凸棒土和活性白土较高添加量相当的脱色效果;活性白土-活性炭复合脱色效果优于凹凸棒土-活性炭,在添加量为2%时,80℃下可使菜籽油的叶绿素含量降低32. 5%、70℃下使菜籽油色泽红值降低30. 6%;双氧水对于去除菜籽油叶绿素和降低色泽红值效果明显,70℃下,0. 4%双氧水(10%)使菜籽油叶绿素含量降低9. 0%、0. 6%双氧水(10%)使菜籽油色泽红值降低25. 0%。活性白土-活性炭脱色和双氧水脱色后的菜籽油品质指标均达到国标四级菜籽油水平;就单位质量浓度脱色剂的脱色效果来说,双氧水的脱色效率更高。

With the color and chlorophyll content of rapeseed oil as evaluation indexes,the bleaching effects of attapulgite,activated clay,activated carbon and hydrogen peroxide on rapeseed oil at medium and low temperature( 40-80 ℃) were compared,and the bleaching effects of composite decolorant including attapulgite-activated carbon and activated clay-activated carbon were also studied. The results showed that the bleaching effect of activated carbon with lower addition amount was equivalent to that of attapulgite and activated clay with higher addition amount. The bleaching effect of activated clay-activated carbon was better than that of attapulgite-activated carbon. With 2% addition amount,the chlorophyll content in rapeseed oil reduced by 32. 5% at 80 ℃,and the red value reduced by 30. 6% at 70 ℃ .Hydrogen peroxide solution had an obvious effect on removing the chlorophyll and reducing the red value of rapeseed oil. At 70 ℃,the chlorophyll content reduced by 9. 0% with 0. 4% hydrogen peroxide solution( 10%),and the red value reduced by 25. 0%with 0. 6% hydrogen peroxide solution( 10%).The quality indexes of activated clay-activated carbon and hydrogen peroxide bleached oils reached the national standard of grade four rapeseed oil. In terms of the bleaching effect of decolorant with unit mass concentration,hydrogen peroxide solution had a higher bleaching efficiency.