Dehydration is one of the safest methods of food preservation and refers to the removal of water which is present in food. In this process, it is not necessary to add preservatives, because bacterium and mold cannot develop in dry places. Without realizing, we use food on a daily basis which has gone through similar processes without any restriction.
There is no shortage of examples of ingredients from which we draw all or part of the water to become dry so they can last longer without the need for preservatives.
The dehydration or drying of foods (solid or liquid), is an operation of water removal, or any other liquid in the form of steam, for an unsaturated gaseous phase using a mechanism of thermal vaporization below the boiling temperature.
Dehydration is carried out using artificially created heat in conditions whereby temperature, moisture and draft are carefully controlled. Air is the most commonly used method in food drying. Air conducts heat to the food, causing water evaporation which is the vehicle transporting moist steam from the food.
Dehydration is the least aggressive process which does not change the structure of food, retaining most of the nutritional content. In the case of vegetables, which originate powered soups, they maintain almost 100% of the vitamins (especially vitamin A) and minerals (selenium, potassium and magnesium).
The use of dehydration is particularly interesting in the case of lactic acid bacteria which is very sensitive to heat.
In general, dehydrated foods does not need to be refrigerated which greatly reduces the costs of storage and transport.
Dehydration leads to a significant reduction in weight which makes food transportation easier and much cheaper.
For example, several foods have up to 90% water, becoming 10 times lighter after the dehydration process.
Most of the dehydrated foods can quickly be re-hydrated back thanks to their porous texture. In fact, dehydration does not lead to a notable reduction of the volume, so the water can easily take its place in the food molecular structure