Evaporation has historically been the primary technology for liquid concentration in the food industry.
Evaporation removes most of the water resulting in concentrated product which may be used as such or processed further, e.g. by drying.
Evaporation is employed in the food industry to reduce weight and volume of fluids, with subsequent reduction of packaging, transportation, and storage costs. It also used to reduce the energy consumption at the drying operation.
Another important application is the production of fruit (mainly grape, apple, and orange) and vegetable (mainly tomato products) juice concentration.
In the dairy industry, evaporation is used for concentration duties, such as milk, skimmed milk and whey. It is also used as a preliminary step to drying. The thermal efficiency of evaporators for removing water is much higher (e.g 90%), compared to the efficiency of dryers (e.g. 60%).
Evaporation of water from the solution by heating is feasible, but usually the products to be evaporated are heat sensitive and heating can change some their physicochemical characteristics at this elevated temperature. Evaporation might result in crustal precipitation.
Evaporation might also result in foaming of the concentrate. Evaporation at low temperatures, under vacuum, reduces thermal degradation of food properties (textural and nutritional) and aroma recovery schemes allow collection of essential flavors and aroma compounds.
Process of evaporation
