Purpose: Since OTA can be found in processed products destined for both human and animal consumption, factors affecting its stability or reduction during thermal processes are investigated.
Methods: Reduction of OTA was measured during variable heating times (up to 60 min) at different temperatures (100, 125, 150, 175, and 200°C) in de-ionized (DI) water and in aqueous buffer solutions at different pH values (pH 4, 7, and 10). Quantification of OTA was carried out with high performance liquid chromatography-fluorescence detection (HPLC-FLD).
Results: The results showed that the rate and extent of OTA reduction or decomposition were dependent on pH, processing time and temperature; greater than 90% of OTA reductions were achieved at 200°C for all the pH variations. After processing under alkaline conditions at 100°C for 60 min, about 50% of OTA was lost, while after 60 min under neutral and acidic conditions at 100°C did not show significant reduction of OTA. These results indicated that while thermal treatment in neutral and acidic conditions may not be enough to reduce OTA, thermal treatment under alkaline conditions yields a more significant reduction of OTA which is increased with increasing temperature.
Significance: This is the first systematic study of the thermal stability of OTA in the absence of a food matrix.