Influence of frying conditions on quality attributes of frying oils: Kinetic investigation of polar compounds

Polar compounds are complex, heterogeneous substances associated with various chronic diseases. In this study, we applied kinetic models to characterise the formation of total polar compounds (TPC), triacylglycerol oligomers (TGOs), triacylglycerol dimers (TGDs), oxidized triacylglycerol monomers (OxTGs), and diacylglycerols (DGs) under different frying conditions. After 32 h of frying, the contents of TPC, OxTGs, TGDs, TGOs, and DGs in the oils ranged from 3.95 % to 35.70 %, 1.63 % to 5.95 %, 2.82 % to 10.87 %, 1.08 % to 9.50 %, and 2.93 % to 16.34 %, respectively. The results revealed variable degradation kinetics across frying systems. Elevated temperatures, frying of chicken nuggets, ferric sulfate addition, and discontinuous frying promoted the formation of OxTGs, TGDs, and TGOs. In contrast, the addition of <i>tert</i>-butylhydroquinone inhibited their formation. These findings provide a kinetic basis for controlling the formation of polar compounds during frying.