高温加热大豆油中反式脂肪酸分析及理化指标变化研究

Detection of Trans-fatty Acid in Soybean Oil Heated with High Temperature and Analysis of Physical and Chemical Indicators

采用毛细管柱气相色谱法分离检测大豆油不饱和脂肪酸高温加热异构化形成的反式脂肪酸(TFA)种类及含量,并比较分析TFA与酸价、羰基价和极性组分等油脂理化指标随加热时间的变化情况。大豆油经220℃高温加热后形成了大量的TFA,加热12 h时TFA含量由对照组的0.075 g/100 g增加至5.691 g/100 g,其种类主要为反式亚油酸和反式亚麻酸。酸价、羰基价和极性组分等理化指标在220℃下随着加热时间的延长而极显著增加(P<0.01),且需要较长的加热时间(48 h以上)才能超过限量值。TFA的含量在加热时间12 h内积累到推荐限量(2 g/100g)的2倍以上。本研究结果为建立高温烹调来源的食用油中TFA限量指标及其控制措施提供科学依据。

The types and content of trans fatty acid（TFA） formed in heated soybean oil were detected by capillary column-gas chromatography method. TFA was comparatively analyzed with physical and chemical indicators（Acid value,Carbonyl group value and Polarity composition） of soybrean oil withdifferent heating time. Soybean oil was heated by high temperature of 220 ℃ with forming the large amounts of TFAs, TFA content increased from control group of 0.075 g/100 g to 5.691 g/100 g after 12 h heating, the main species were trans linoleic acid and linolenic acid. Physical and chemical indicators such as acid value, carbonyl group value and polar components significantly increased（P 0.01） with heating time extended under temperature of 220 ℃, but longer heating time（more than 48 h） was needed to exceed the set limit value of these indicators. While the TFA content in the 12 h of heating time was more than 2 times of the recommended limits（2 g/100 g）. This study provided a scientific support for establishing limited index of TFA and its control method in edible oils heated under high temperature.