Maillard reaction progress in UHT milk during storage at different temperature levels and cycles

Elevation and fluctuation in storage temperature of UHT milk can result in chemical reactions that may affect quality; hence understanding changes related to shelf-life conditions is of high value for the dairy industry in improvement of storage stability and quality control. A study on progress of Maillard related quality parameters was thus carried out on skimmed and full fat UHT milk stored for 24 weeks at various temperatures. All three stages of Maillard reaction were possible to describe in Arrhenius plots, and data obtained provided temperature sensitivities and kinetics, with the intermediate phase being the most temperature sensitive. Fluctuations in temperature are often encountered during export and storage of UHT products, therefore temperature cycles were included to somehow simulate real life conditions. The effect of temperature cycles was most pronounced at higher temperatures resulting in increased reaction rates and revealed different temperature dependencies of the Maillard reaction.