高温模拟烹饪试验中食用植物油反式脂肪酸的含量变化

Trans-fatty acid content in edible vegetable oil under different high temperatures

【目的】提出食用植物油中反式脂肪酸(TFAs)含量的测定方法,分析高温模拟烹饪过程中食用植物油TFAs的含量变化情况。【方法】选取市场上5种常见的食用植物油,分别设置180℃(轻炒)、220℃(炸)和260℃(爆炒)3个温度点对样品进行高温模拟烹饪试验。于0、1、2、3、4、5、6、7 h后取样,观察TFAs含量随时间变化的趋势。【结果】在180℃和220℃的条件下菜籽油、玉米油、大豆油和橄榄油等4种食用植物油的TFAs含量基本保持稳定。在加热到260℃条件下4种植物油TFAs含量均明显增加,菜籽油中TFAs含量绝对值最高,达到6.84%;大豆油增幅较大,较最初增加247.90%;橄榄油TFAs含量由0.26%增长至1.69%,增幅虽大,但TFAs绝对含量仍较低。芝麻油在3个温度梯度下TFAs含量均明显增加,在260℃加热条件下TFAs含量达到4.79%,较未加热时增长369.61%。【结论】食用植物油在烹饪过程中,温度越高、时间越长,TFAs含量增幅越显著,建议尽量避免高温长时间烹炸食品。

[Objective]An experimental method was established to determine the level of trans-fatty acids in edible vegetable oil and the changes of trans-fatty acid content during high-temperature simulated cooking.[Methods]Four common edible vegetable oils on the market were selected,and three temperature points were set at 180℃(light stir-fry),220℃(fry)and 260℃(stir fry).The samples were taken after the heat treatment of 0,1,2,3,4,5,6 and 7 hours,respectively,to investigate the changes of trans-fatty acid content.[Results]Under the heat treatment of 180℃and 220℃,the content of trans-fatty acids remained basically stable in rapeseed oil,corn oil,soybean oil and olive oil.Under the heating condition of 260℃,the content of trans-fatty acids in these four vegetable oils increased significantly,and the absolute content of trans-fatty acids in rapeseed oil was the highest,reaching 6.84%.Soybean oil showed the larger increase,up to 247.90%from the initial content.The content of trans-fatty acids in olive oil increased from 0.26%to 1.69%,although the increase was large,but the absolute content of trans-fatty acids was still low.The content of trans-fatty acids in sesame oil increased significantly under the three temperatures,reaching 4.79%when heated at 260℃,and an increase of 369.61%compared with no heating.[Conclusion]Trans-fatty acid content in edible vegetable oils increases significantly in the cooking process,the higher the temperature and the longer the cooking time,the more significant the increase.It is recommended to avoid high temperature cooking and long time fried food.