RESUMO
This study evaluated the validity of total polar compounds (TPC) and its three components in monitoring the evolution of epoxy fatty acids in frying oil under fast food restaurant conditions. The content of epoxy fatty acids can be predicted using the TPC rather than oxidized triglyceride monomer. When TPC content reached 24 g/100 g, 25 g/100 g, and 27 g/100 g, the epoxy fatty acid content in oil was found to be 1.47-3.63 mg/g, 1.58-4.06 mg/g, and 1.83-5.08 mg/g, respectively. More epoxy fatty acids were generated in high oleic sunflower oil than in canola and cottonseed oil during frying. At current discarding points of TPC 24-27 g/100 g, its epoxy fatty acid content was 3.63-5.08 mg/g, which was lower than the limit of 7 mg/g recommended by Max Rubner-Institut in Germany. Our results indicate that the risk of epoxy fatty acids can be monitored using the current TPC index.
Assuntos
Fast Foods , Restaurantes , Ácidos Graxos , Óleo de Sementes de Algodão , Óleo de GirassolRESUMO
This work evaluated the feasibility of total polar compound (TPC) and its five components to monitor the deterioration of soybean oil at frying temperatures, and traditional indicators were used as a reference. The preliminary correlation analysis showed that polar compounds accumulated earlier than classical oxidation products like the peroxide value (PV). Equations for two types of characteristic kinetic time, the induction time (turning point of sigmoid curve) and intersection time (intersection point of two tangent lines representing the initiation and propagation reaction), were also derived. Their mathematical difference and relationship were then evaluated. Based on the kinetic analysis, the overall cumulative process of oxidation products of triglycerides (oxTGM) was found to be 2.35%-12.35% earlier than that of fatty acids (PV). Our results supported the index of oxTGM in TPC to be a better indicator to monitor the deterioration of heated edible oil.