Thermal stability of deoxynivalenol, zearalenone, and their modified forms during baking in oat biscuits

The present study aimed to investigate the effects of the baking process on some Fusarium mycotoxins (deoxynivalenol (DON), zearalenone (ZEN), T-2 and HT-2 toxins) and their modified forms (deoxynivalenol-3-glucoside (DON-3G), 15-acetyldeoxynivalenol (15-ADON), 3-acetyldeoxynivalenol (3-ADON), deepoxy-deoxynivalenol (DOM-1), α-zearalenol (α-ZEL), and β-zearalenol (β-ZEL)) in oat biscuits. Their content was analysed using HPLC-DAD and UHPLC-MS/MS to evaluate the impact of temperature, time and initial mycotoxin concentration. Also, metabolite screening (sulphated ZEN metabolites, isoDON and norDONs) was performed to provide new insights into the baking effect on mycotoxins. Results indicated that mycotoxin reduction depended significantly on baking temperature and duration. ZEN exhibited higher thermostability than DON-3G, and DON-3G was more thermostable than DON. Under harsh conditions, 15-ADON decreased while DOM-1 increased. isoDON and norDONs emerged during baking. Initial baking phases showed increased levels of ZEN, α-zearalenol-14-S (α-ZEL-14-S) and β-zearalenol-14-S (β-ZEL-14-S) due to the release of hidden mycotoxins, raising safety concerns. T-2 and HT-2 toxins were not found in any oat-based product. The final edible biscuits for each temperature exhibited similar DON and DON-3G concentrations, with higher ZEN levels than initially. Degradation kinetic analysis revealed zero-order kinetics for DON and DON-3G and first-order kinetics for ZEN, offering a predictive tool for mycotoxin levels in biscuits. • DON, ZEN, and their modified forms were studied during oat biscuits baking. • Baking reduced DON and DON-3G, but their concentration increased from weight loss. • Harsh baking conditions led to decreased 15-ADON levels and increased DOM-1 levels. • isoDON and norDONs emerged during baking. • ZEN, α-ZEL-14-S and β-ZEL-14-S levels increased due to the release of hidden forms.