红外光谱法分析加热对食用油成分变化影响的研究

Analysis of oil main components changes during the heating process by infrared spectroscopy

以绿珍珠牌特级初榨橄榄油、鲁花压榨葵花籽油、金龙鱼食用调和油和鲁花5S一级压榨花生油等四种具有代表性的食用油为研究对象,将其用恒温磁力搅拌器分别加热到100℃、120℃、150℃和180℃并保持1小时,冷至室温后在4000~400cm^(-1)范围内进行红外扫描。结果表明:常温时四种食用油主要成分差别不大;加热后四种食用油的不饱和脂肪酸含量都降低,饱和脂肪酸的含量均增加,甘油三酯、碳骨架等也受到不同程度的影响;其中受温度影响最大的是金龙鱼食用调和油,加热至120℃时其不饱和脂肪酸的含量开始降低,继续加热至180℃时含量剧烈下降至不足常温的四分之一,而饱和脂肪酸的含量则迅速上升。该方法操作简便,结果可靠,建议人们烹饪时,尽量不要长时间高温加热食用油。

Green Pearl extra virgin olive oil, Luhua sunflower seed oil , Arawana blend oil and Luhua 5S level pressed peanut oil were heated to 100℃, 120℃ 150℃ and 180℃ for 1 hour. Then they were scanned at the wave lengthof 4000 - 400cm^-1 by IR spectrum. The results showed that heating caused four kinds of unsaturated fatty acids decrease and saturated fatty acids increase. It also caused changes of carbon skeleton and triglyceride （TG）. The most temperature affected oil was Arowana blend oil, its saturated fatty acids started to decrease when heating to 120℃ and decreased dramatically at 180℃, at the same time, the saturated fatty acids raised rapidly. Therefore, it is better not to heat oil for long time during cooking.