KINETICS OF NONENZYMATIC BROWNING IN CHEDDAR CHEESE POWDER DURING STORAGE

Nonenzymatic browning (NEB) in Cheddar cheese powder during storage wa s investigated in the water activity (a(w)) and temperature ranges of 0.48-0.85 and 20-40C, respectively. The NEB obeyed zero-order reaction kinetics during storage. Activation energies and Q(10) values were in the range of 15.1-22.3 kcal/mole and 2.2-3.5, respectively. The NEB i ncreased with increasing temperature and storage time. There was an a( w) maxima at 0.63 for NEB at 20C. At 30 and 40C, NEB decreased with in creasing a(w). A generalized NEB model for Cheddar cheese powder durin g storage was developed based on Arrhenius equation to describe NEB as a function of a(w) and temperature. Powders stored at 20 and 30C were evaluated for quality aspects. Maximum storage stability was obtained in powders stored at a(w) of 0.54 at 20C for five months based on an overall desirability score of 3.5 on a 7-point scale. The average scor e of fresh powders were 4.7 throughout the storage study 7.