6种油脂和大豆粉、菜籽粉氧化指标及其脂肪酸组成的变化

在人工氧化条件下,测定猪油、豆油、大豆粉、菜籽油、菜籽粉、江苏棉籽油、新疆棉籽油、罗非鱼油的酸价、碘值、过氧化值、丙二醛、脂肪酸组成。结果表明:①罗非鱼油所测定的氧化指标变化较其它油脂明显,其氧化稳定性最差;②猪油、罗非鱼油、棉籽油、菜籽油、豆油在氧化过程中过氧化值(POV)变化明显,应该成为油脂氧化程度评价的通用性指标;③大豆粉和菜籽粉的氧化指标变化最小,且其氧化稳定性明显好于相应的油脂;④0～70h内,随着氧化时间的延长,各油脂的脂肪酸组成有一定的变化。结论:在氧化过程中,不同种类油脂的氧化指标敏感度有差别,评价油脂氧化程度时应根据油脂种类选择氧化指标进行评价;在油脂氧化初期阶段,用脂肪酸的组成变化来表征油脂在氧化过程中品质的变化现象并不明显。

Changes of oxidation indicators and fatty acid composition of six kinds of fats and soybean meal, rapeseed meal

In the artificial oxidation conditions,we measured acid value,iodine value,peroxide value,MDA and fatty acids of lard,soybean oil,soybean meal,rapeseed oil,rapeseed meal,cottonseed oil from Jiangsu and Xinjiang,and tilapia oil.The results indicate: ①Changes of measured oxidation indicators of tilapia oil were more obvious than other oil with the worst oxidation stability;②The indicator(POV) of lard,tilapia oil,cottonseed oil,rapeseed oil and soybean oil significantly changed in the oxidation process,therefore it should become the common evaluation indicators;③Changes of the oxidation indicators of soybean meal and rapeseed meal were the smallest,and the oxidative stability was significantly better than their corresponding oil;④ During the 70 hours period,with the extention of oxidation time,the fatty acid composition of the oil were not significantly changed.In the oxidation process,sensitive indicators of different types of fat are different.To evaluate oil oxidation,the indicators should be selected according to each type of fat.In the early stage of oil oxidation,it is not obvious to characterize the quality of the oil with the change of fatty acid composition.