美藤果油和普洱茶籽油的主要脂肪酸组成及氧化动力学研究

采用气相色谱-质谱法测定美藤果油和普洱茶籽油的主要脂肪酸组成,并利用热重分析法(thermogravimetric analysis,TGA)测定不同升温速率下两种植物油的起始氧化温度(Ton)和氧化峰值温度(Tp),并对两种植物油的动力学参数进行求解。结果表明:美藤果油和普洱茶籽油的不饱和脂肪酸含量分别为92.89%、79.08%;随着升温速率的增加,两种植物油的Ton和Tp均随之升高。由热重分析法计算出在Ton处的活化能分别为:美藤果油123.5 kJ/mol;普洱茶籽油125.7 kJ/mol。美藤果油在Tp处的活化能是150.9 kJ/mol,普洱茶籽油是127.6 kJ/mol。总体来看,两种植物油都具有很好的热稳定性。

Main Fatty Acid Composition and Oxidation Kinetics of Sacha Inchi Oil and Puer Tea Seed Oil

The main fatty acid composition of the sacha inchi oil and the Puer tea seed oil were analysed by gas chromatography-mass spectrometry(GC-MS). The onset oxidation temperature(Ton)and peak oxidation temperature(Tp)of the two vegetable oils under different heating rates were determined by thermogravimetric analysis(TGA)and the kinetic parameters of the two vegetable oils were calculated. The results showed that the percentage of unsaturated fatty acid the sacha inchi oil and Puer tea seed oil were 92.89 %,79.08 %,respectively. Ton and Tp of two vegetable oils were increased with the increase of heating rate. The activation energy of sacha inchi oil and Puer tea seed oil for Tonor Tpcalculated by thermogravimetric analysis were 123.5,150.9,125.7 kJ/mol and 127.6 kJ/mol,respectively. In general,two vegetable oils had good thermal stability.