Milk skin formation during drying

Abstract

Mass transfer during the drying of skim milk and whole milk films is examined using a combination of experiments and mathematical modeling. Microwave power is used rather than the traditional convective heating characteristic of spray drying to provide greater heating uniformity. In all experiments a period of constant rate drying is observed, followed by a period of diffusion control that is characterised by a rapid increase in sample temperature. The onset of diffusion control is shown to be directly related to the amount of both fat and protein in whole milk samples and to the amount of protein in skim milk samples. These changes occur as a result of the lower diffusivity of protein and f..