微波预处理对油菜籽及其低温压榨油脂肪酸含量的影响

为了解微波预处理对油菜籽及菜籽油脂肪酸含量的影响，评价其产生反式脂肪酸的风险，以8个省14产地的57份油菜籽样品为材料进行微波预处理，并对微波前后的油菜籽进行压榨，得到冷榨菜籽油。采用优化后的气相色谱法快速测定油菜籽和菜籽油中脂肪酸组成和含量，考察油菜品种、油菜产地以及微波预处理对油菜籽脂肪酸含量的影响。结果发现，与国标方法相比，优化后样本分析时间缩短一半以上，显著提高分析通量。研究发现，产地对油菜籽和冷榨菜籽油脂肪酸组成和含量影响较小，品种对菜籽和冷榨菜籽油脂肪酸组成和含量影响较大。不同品种的油菜籽和对应冷榨菜籽油中的脂肪酸含量差异极显著（P＜0.01）。高芥酸菜籽的花生一烯酸、芥酸的平均含量分别是低芥酸菜籽的6.89倍和64.50倍，油酸的平均含量仅为低芥酸菜籽的71.48%。同一品种不同产地的油菜籽与对应的冷榨菜籽油中的脂肪酸含量之间，不存在显著性差异。微波预处理不会显著影响油菜籽和菜籽油中的脂肪酸组成和含量水平，同时也不会产生反式脂肪酸等风险因子，微波处理后，产生反式脂肪酸的风险较低。

Effects of microwave pretreatment on fatty acid content of rapeseed and cold-pressed rapeseed oil

To investigate the effect of microwave pretreatment on fatty acid, and evaluate to the risk of trans- fatty acids in rapeseed and cold-pressed rapeseed oil, 57 rapeseed samples from 14 producing areas in 8 provinces of China were used for microwave pretreatment test. The rapeseeds (both before and after microwave treatments) were pressed to obtain cold-pressed oil. Fatty acids were quickly determined by using optimized gas chromatography method which reduced the analysis time by more than 50%. Results showed that variety was the main factor (p＜0.01) affecting the fatty acid composition and contents, while origin had no statistically significant effect. The average content of eicosenoic acid and erucic acid in low erucic acid rapeseed were 6.89 and 64.50 times higher than that in high erucic acid rapeseed, respectively. The average oleic acid content of high erucic acid rapeseed was only 71.48% of the high erucic acid rapeseed. Thus microwave pretreatment might not significantly affect the composition and content of fatty acids in rapeseed and rapeseed oil. It neither brought risk of trans-fatty acids.