Abstract Measurement of total polar compounds (TPC) is recognised as one of the objective indicators to gauge oil resistance against high temperature. Dependency to TPC measurement alone in arbitrating the quality and safety of oils can be misleading especially for those oils that are rich with significant amount of natural diacylglycerols (DAG). In fact, the results generated could be at the higher side when the analysis protocol involves excessive drying. Method modification has been established to isolate and quantify the individual polar compound fractions without the involvement of drying stage to protect the integrity of samples and therefore produce credible results. Performance of the established method is validated with the DAG quantified from the acylglycerols analysis. A series of vegetable oils, i.e. palm olein (POo), soybean oil (SBO), canola oil (CAN) and sunflower oil (SFO), were subjected to 9 days of intermittent frying, 8 h day−1 and 144 frying cycles. The transient of TPC across frying time was coincided with polymerised triacylglycerols (PTAG) following the linear model with coefficient of determination (R2) greater than 91% while DAG and oxidised triacylglycerols (OxTAG) showed good regression with the quadratic model (R2 > 0.97). Oils with equal amount of polyunsaturated fatty acids (PUFA) were found to have similar rate of combined PTAG and OxTAG. Whilst liquid oils have similar OxTAG contents with POo, they were much distressed with polymeric reaction given that their PTAG levels were 1.6–2.4 folds higher than POo. Blending liquid oils with POo has been proven to moderate the level of PTAG when similar frying conditions were applied.

中文翻译：

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在快餐店模拟煎炸实践下通过植物油中极性化合物的分配对油降解的公正评估

摘要 总极性化合物（TPC）的测量被公认为是衡量耐高温油性的客观指标之一。在仲裁油的质量和安全性时仅依赖于 TPC 测量可能会产生误导，尤其是对于那些富含大量天然二酰基甘油 (DAG) 的油。事实上，当分析协议涉及过度干燥时，生成的结果可能会偏高。已经建立了方法修改来分离和量化各个极性化合物部分，而无需涉及干燥阶段，以保护样品的完整性，从而产生可靠的结果。已建立方法的性能通过从酰基甘油分析中量化的 DAG 进行验证。一系列植物油，即棕榈油精（POo）、大豆油（SBO）、菜籽油 (CAN) 和葵花籽油 (SFO) 进行了 9 天的间歇油炸、8 小时第 1 天和 144 次油炸循环。TPC 在油炸时间内的瞬变与聚合三酰甘油 (PTAG) 符合线性模型，决定系数 (R2) 大于 91%，而 DAG 和氧化三酰甘油 (OxTAG) 在二次模型中显示出良好的回归 (R2 > 0.97) . 发现具有等量多不饱和脂肪酸 (PUFA) 的油具有相似的 PTAG 和 OxTAG 组合率。虽然液体油的 OxTAG 含量与 POo 相似，但由于它们的 PTAG 水平比 POo 高 1.6-2.4 倍，因此它们对聚合反应非常不利。当采用类似的油炸条件时，将液态油与 POo 混合已被证明可以降低 PTAG 的含量。