1. In drying:
(a) the latent heat of vaporization must be supplied and heat transferred to do this.
(b) the moisture must be transported out from the food.
2. Rates of drying depend on:
(a) vapour pressure of water at the drying temperature,
(b) vapour pressure of water in the external environment,
(c) equilibrium vapour pressure of water in the food
(d) moisture content of the food.
3. For most foods, drying proceeds initially at a constant rate given by: