Effects of infrared heating on phenolic compounds and Maillard reaction products in maize flour

Maize grains were heated by infrared radiation for 50–100 s, than flaked and milled. The output was set to 110, 115, 120 and 140 °C to determine the effect of temperature on the formation of acrylamide, 5-hydroxymethylfurfural (HMF) and furosine, as well as the level of phenolic compounds in maize flour and its total antioxidant capacity (TAC). Acrylamide and HMF levels were increased as the load of the heat treatment was increased in grains, while furosine concentration was rapidly increased to an apparent maximum (34.96 μg/g) followed by decrease during heating. Acrylamide, as well as HMF variables correlated very well with TAC of heat-treated flour (r² = 0.98 and 0.86). The process of infrared heating had a great influence on the reduction of phenolic compound contents. However, new antioxidants that were formed as a result of the Maillard reaction increased the total antioxidant capacity of heat-treated maize flour.