The destruction of enzymes and bacteria during the spray drying of milk and whey 2. the effect of drying conditions
Daemen, A.L.H.; Van-Der-Stege, H.J.
Netherlands Milk and Dairy Journal 36(3): 211-230
The destruction of some enzymes and bacteria during the spray-drying of milk and whey under various conditions is discussed. In particular, the effect of air temperature, total solids content of the concentrate, particle size, air inclusion and method of atomization were studied. The outlet air temperature had a large effect, but the effect of the inlet air temperature was only slight. The effect of the former can best be expressed by a pseudo z value; calculation of the activation energy of the destruction process was not really possible. It was expected that a larger particle size would corespond to a greater destruction, but the inclusion of air in the particles masked this effect. The destruction of bacteria had not only to be ascribed to a thermal effect, but also to a non-thermal drying effect.