ABSTRACT
The study on mass transfer involves movement of component(s) in a mixture either within the same phase or from one phase to the other. This movement is governed by concentration gradient across the two points of interest. This movement ultimately leads towards the phase equilibrium. There are many situations in food processing where proper mass transfer operation yields a desirable result. Mass transfer involving different geometries also follows similar expressions in heat transfer. Three is analogy among all the three transfer processes, namely momentum, heat and mass transfer. Basically the mechanism of mass transfer is the movement of individual molecule through a substance in a straight line in random manner and at constant velocity until it collides with other molecules. Mass transfer of gasses and liquids in solids is an important in food processing. Diffusion of gas occurs in many food processing operations like freeze drying of foods wherein vapour moves through very fine capillary in the porous solid.
