A KINETIC-STUDY ON 5-HYDROXYMETHYLFURFURAL FORMATION IN SPANISH UHT MILK STORED AT DIFFERENT TEMPERATURES

5-Hydroxymethylfurfural (HMF) formed at different storage temperatures (below 50 degrees C) in commercial ultra high temperature (UHT) milk was measured both by colorimetric and RP-HPLC techniques. Lowest HMF a mounts were noted in all samples by RP-HPLC method. HMF level was foun d to be related to temperature and time of storage and increased at hi gher temperature, although small losses were detected at 6 degrees C. Two stages of HMF formation could be differentiated, i.e., at an early stage till first 60 days and an advanced one from so days until 90 da ys. Zero order kinetics were obtained for both stages, along with high er activation energy values for UGT-indirect samples.