Effects of dissolved oxygen on the Maillard reaction during heat treatment of milk

The effects of dissolved oxygen (DO) on the Maillard reaction during heat treatment of milk were investigated. In a pilot plant test, the aminoreductone (AR) concentration, a Maillard reaction product, in deaerated milk was significantly higher than that in non-deaerated milk. In a small-scale heating test, the decrease in the oxygen concentration in the vial during heating was larger when the milk contained more DO before heating. In addition, the AR concentration after heating inversely correlated with the decrease in the oxygen concentration in the vial. The AR formation was constant during heating; however, it was oxidatively degraded by interacting with DO. Thus, the lowering in DO concentration of raw milk before heat treatment enables the suppression of oxidative degradation of AR during heating, thereby maintaining high AR concentration after heating.