ABSTRACT
This chapter examines the mass transfer by diffusion and convection, and depletion by chemical reactions is modeled for an infinite slab, applied to hydrogen ion transfer and depletion in meat emulsions during cooking. Mass transfer in foods can occur in the form of liquid and gases in liquid and solid due to concentration gradient and convection. Mass transport is required in the analysis of basic food processing operations such as drying, crystallization, humidification, distillation, evaporation, leaching, absorption, membrane separation, rehydration, mixing, extraction, and storage. Capillary or the liquid diffusion theory is generally applicable to the mass transfer in food materials. Molecular diffusion is the movement or transfer of individual molecules through a stationary fluid by means of random movements. Mass transfer by turbulence motion is very rapid compared to molecular diffusion alone. Heat, moisture, and fat transfer both within and around the food, and the formation of a crust, is the basis of deep-fat frying.
