The falling rate period allows for the continuous movement of water to the food’s surface provided there is sufficient moisture inside the wet material, thereby creating this expanded surface water film.

The constant rate period allows for the evaporation of the surface moisture of the food to the point where the inside of the material cannot reach the surface quickly enough to replenish the surface water film.

A 0.5-inch cubed carrot will dry faster than a 1-inch sample.

A more porous sample like apple slices will not dry quickly.  

When high moisture products are dried too rapidly, the surface may become overly dry and develop a shell impervious to moisture.

When moisture is removed from food, the moisture from the inside will carry all the soluble constituents, thus promoting leaching.  

The addition of sugar in mangoes reduces its water activity through the process of osmotic dehydration.   

As the inlet temperature is increased in a spray dryer, residual moisture content is reduced.

The higher the dextrose equivalent of the carrier agent in spray drying, the more hydrophilic it is, the more moisture is absorbed.

Traditional sun drying loses moisture through sublimation.

During the early stages of drying, the surface is saturated with a ‘pool’ of moisture that evaporates and is carried by warm dry air.

100 kg red bell peppers with 77% moisture would contain 80 kg of water and 20 kg of solids.

Natural sugars are concentrated when drying fruits, hence the sweet taste.