Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University , Beijing 100048, China.
School of Food and Chemical Engineering, Beijing Technology and Business University , Beijing 100048, China.
J Agric Food Chem. 2016 Jul 27;64(29):5919-27. doi: 10.1021/acs.jafc.6b01520. Epub 2016 Jul 18.
In the present study, the formation mechanisms of glycidyl fatty acid esters (GEs) were investigated both in real edible oils (soybean oil, camellia oil, and palm oil) during laboratory-scale preparation and refining and in chemical model (1,2-dipalmitin (DPG) and 1-monopalmitin (MPG)) during high temperature exposure (160-260 °C under nitrogen). The formation process of GEs in the chemical model was monitored using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. The results showed that the roasting and pressing process could produce certain amounts of GEs that were much lower than that produced in the deodorization process. GE contents in edible oils increased continuously and significantly with increasing deodorization time below 200 °C. However, when the temperature exceeded 200 °C, GE contents sharply increased in 1-2 h followed by a gradual decrease, which could verify a simultaneous formation and degradation of GEs at high temperature. In addition, it was also found that the presence of acylglycerol (DAGs and MAGs) could significantly increase the formation yield of GEs both in real edible oils and in chemical model. Compared with DAGs, moreover, MAGs displayed a higher formation capacity but substantially lower contribution to GE formation due to their low contents in edible oils. In situ ATR-FTIR spectroscopic evidence showed that cyclic acyloxonium ion intermediate was formed during GE formation derived from DPG and MPG in chemical model heated at 200 °C.
在本研究中，通过实验室规模的制备和精炼研究了真实食用油（大豆油、茶籽油和棕榈油）和化学模型（1,2-二棕榈酸甘油酯（DPG）和 1-单棕榈酸甘油酯（MPG））中缩水脂肪酸酯（GEs）的形成机制。在高温暴露（氮气下 160-260°C）期间，使用衰减全反射傅里叶变换红外（ATR-FTIR）光谱监测了化学模型中 GEs 的形成过程。结果表明，烘烤和压榨过程会产生一定量的 GEs，但远低于脱臭过程中产生的量。在低于 200°C 的脱臭过程中，食用油中的 GE 含量会随着脱臭时间的增加而不断显著增加。然而，当温度超过 200°C 时，GE 含量会在 1-2 小时内急剧增加，随后逐渐减少，这可以证明在高温下 GEs 会同时形成和降解。此外，还发现甘油酯（DAGs 和 MAGs）的存在会显著增加真实食用油和化学模型中 GEs 的形成产率。与 DAGs 相比，MAGs 由于在食用油中的含量较低，形成能力更高，但对 GE 形成的贡献却要低得多。原位 ATR-FTIR 光谱证据表明，在化学模型中，加热至 200°C 时，DPG 和 MPG 衍生的环状酰氧鎓离子中间体形成了 GEs。
