food preservation

Freeze-dried food and freeze-drying

Freeze-drying is a particular drying process that has the purpose of increasing the shelf-life of a product, preserving almost completely its nutritional and organoleptic characteristics.

The freeze-dried foods are used above all for the preparation of broths, soups, ready-to-eat baby food, homogenized meats and vegetables.

Foods destined for freeze-drying, often of biological and controlled origin, are initially chopped into small parts and eventually cooked and subjected to homogenization.

The actual freeze-drying process begins with the freezing of the chopped foods, which are brought to a temperature between -30 and -50 ° C. This first step is necessary to block the degenerative processes of the food. Subsequently it proceeds with drying under high vacuum. The entire process, which exploits the physical and chemical properties of water, takes place in controlled environments and is called crioessiccamento. The packages are then hermetically sealed, so as to maintain the degree of dryness reached (less than one, maximum 2% humidity).

The complete dehydration of the food, in addition to not altering its original characteristics, makes it possible to obtain products (freeze-dried) of significantly lower weight and volume (from 1/4 to 1/10) compared to the starting food. A freeze-dried food thus brings considerable advantages also in transport and storage operations.

If these characteristics are particularly valuable in the industrial field, the final consumer especially appreciates their practicality. It is in fact sufficient to reconstitute the freeze-dried foods with water to obtain a complete, practical and nutritious food. Often consumers, unaware of the complex procedure required to obtain freeze-dried foods, raise doubts about their safety. As mentioned at the beginning of the article, the foods subjected to freeze-drying maintain the organoleptic characteristics of the raw material of departure unaltered. Furthermore the fine fragmentation facilitates the digestive processes making them suitable above all for feeding children and convalescents. To make sure of the quality of the food, it is sufficient to read the label where the ingredients and nutritional characteristics appear clearly.

Once the package is open, place the remaining product in a sealed package, away from moisture.