Abstract
The impact of a UHT treatment on a model infant formula was examined by assessing the advancement of Maillard reactions during a thermal treatment by ohmic heating. The heating and holding steps of the heat treatment were carried out in a static batch ohmic heater equipped with a nitrogen counter-pressure system, allowing reaching five temperature levels from 100 to 140 °C. A heat treatment was characterized by monitoring a holding time at a given temperature. Samples were taken during heating and holding steps and analysed for early Maillard reactions products (MRPs) as furosine, advanced MRPs as advanced glycated end products (AGEs) and carboxymethyl-lysine (CML) and final MRPs as melanoidins. The results show that Maillard reactions in model infant formula are highly dependant from time-temperature treatment. In compliance with other classical heating techniques, the selected chemical markers followed a pseudo-zero order of reaction under isothermal conditions. However, the contribution of the heating step can be significant as Maillard reactions products could be detected from the first seconds of the UHT treatment.