Freeze drying is a technique used for the preservation of food and medicines. It is an industrial method for drying things at temperatures below freezing.
For food, freeze-drying basically involves four steps. The food is first prepared. Then it is quickly frozen at very low temperatures (approximately -40 °C). This reduces the chance of damage caused by freezing. The faster the food is frozen, the smaller the ice crystals will be. This in turn is better for the drying process.
After freezing, the food is dried in two steps. First, at a reduced air pressure, the majority of the ice is slowly removed by sublimation, which takes several days. This means that the ice does not defrost first, but evaporates directly from its solid form. This drying process takes place at a temperature that is tens of degrees below freezing. Sublimation does take longer under these low temperatures, but this process does ensure optimum preservation of flavour and texture. In the final stage, the food is dried to remove the last traces of water.
Advantages of Freeze-drying
Freeze drying of food has the following advantages:
- The general advantage of freeze drying is improved preservation. Micro-organisms such as bacteria cannot multiply in a too dry environment.
- The shelf life of the food is extended considerably.
- The food retains all its good nutrients. Freeze-dried fruit and vegetables, for example, remain full of vitamins and minerals.
- The taste and texture are better preserved this way.
- The volume and weight decrease, so the food takes up less space.
Freeze Dried products
There are many fruit and vegetable products that can be freeze-dried to retain their healthy properties and extend their shelf life. Our range includes the following freeze dried products: