Air-fryer vs. traditional oven: Influence of flour type on acrylamide, HMF, and furfural formation in cereal-based biscuits

Air-fryers are increasingly used for home baking, yet their impact on heat-induced contaminant formation remains unclear. This study evaluated the influence of flour type and baking system on the formation of acrylamide, hydroxymethylfurfural (HMF) and furfural in cereal-based biscuits prepared using two air-fryers (static- and rotating-basket models) and a conventional oven. Biscuits made with refined and wholegrain flours from wheat, rye, spelt, oat, and buckwheat were baked under comparable nominal conditions (175 °C, 12 min). Acrylamide levels varied markedly with flour type and baking device, ranging from 81 to 1320 μg/kg. The static-basket air-fryer produced the highest acrylamide and HMF levels (up to 1320 μg/kg and 79.8 mg/kg), whereas the rotating-basket air-fryer yielded values similar to conventional oven baking. Buckwheat biscuits consistently exhibited the lowest acrylamide levels and among the lowest HMF concentrations. Overall, the results demonstrate that air-frying is not inherently safer than conventional baking, as high-intensity convective heat transfer can accelerate Maillard reaction kinetics and offset formulation-based mitigation strategies.