Drying (food)
Drying refers to various methods for the preservation of food by air drying. The term is derived from the kiln, of the lattice- like device, which is used from of old for drying.
Drying is probably the oldest method of preservation at all. Nowadays most rapid drying process such as freeze drying or spray drying can be used for industrial applications. Therefore, the desiccating found mainly still for drying smaller quantities of food in agricultural or household current frame application.
Principle
The aim of the Dörrens is dehydration, so to avoid the foods as much water as possible. Thus, the basis of life is the microorganisms that cause spoilage, withdrawn and extends the shelf life of the food with it. Most bacteria do not proliferate more from a water content of less than 35 percent. Many fungi, however, are disintegrating still working up to a water content of 15 percent.
In Drying of water withdrawal takes place in that dry, warm air flows past the food. It evaporates the moisture layer on the surface of the food. From the interior of the food after the water flows, which evaporates again at the surface, until the water content of the food for a further subsequent flow is too low. The moist dried air is discharged into the environment.
Dried temperature and time
Unlike the sterilization heating causes no destruction of the microorganisms, but only the removal of water. The higher the temperature of the dried air, and the greater the permeability of the fabric of the food and its surface area, the faster the drying. The temperature should not be too high, because heat can destroy valuable nutrients and undesirable chemical processes trigger (eg, tanning ). Too low a temperature, however, delayed the torrefaction and gives the rot pathogens too much time to attack the food to be dried.
When sliced or slices fruits, vegetables and fungi, temperatures between 30 and 70 ° C are suitable in order to achieve a dried degree of 25 to 50 percent after a drying time from 6 to 12 hours depending on the crop. Grains ( corn, grain, seed, seeds, nuts) can reach a dehydrator of 80 to 90 percent after four to six hours of drying. Herbs can be dried in ambient air for two to three weeks, or about two minutes in a microwave oven.
Pros and Cons
Compared to other methods of preservation the Dörren has among others the advantage that the food with the removal of water is smaller and lighter, which makes them easier trans -port and store. The vitamins, minerals and dietary fibers of Dörrguts remain. The Drying can change the taste and consistency of the food and thus open up new uses.
One of the disadvantages of Dörrens heard that it does not kill the rot pathogens and spoilage therefore only delayed. Depending on the method, it is also connected to a relatively long time and / or energy consumption.
Dehydrator method
The easiest food is parched by being exposed to the dry ambient air. It is placed on to a dryer ( kiln ) or in the Palatinate traditionally in a wicker basket (fruit nurseries, Hoertel ), or strung on a string. The dehydrator room must be dust -free and have good air circulation and low humidity. Because the Drying at ambient temperature takes a long time, the food to be dried must be turned regularly and checked for mold.
Air drying can also be done in a specially constructed oven, are used in the dryer fabrics. The drying capacity can be increased by a heat source and / or a fan are used on the ground. Solar dehydrator are drying ovens, which use the heat of the sunlight for drying.
Also in the oven can be parched food. It is placed on lined with baking paper gratings. The moisture escapes through a gap wide open oven door.
There is Dehydrators for household use. They consist of a heating element and a blower that blows the air heated up by the stacked, covered with the dried food dryer fabrics.
Dörrbare food
To foods which can be preserved by dehydrating include:
- Fruit ( dried fruit ), in slices or pieces, with or without shell; or as dried fruit puree ( fruit paste, fruit leather).
- Vegetables, especially cabbage, onions and root vegetables into slices or pieces
- Mushrooms ( dried mushrooms ).
- Grains, seeds and nuts.
- Meat ( dried meat, smoked meat )
- Fish ( cod, salted codfish )
Storage of dried food
Dehydrated food contains a residual humidity of 10 to 15 percent. In order to prevent spoilage, especially mold, it must air-and moisture-proof packaging to be stored dark and cool. Commercially produced dried fruit is often also sulfurized to extend shelf life.
A storage pest that attacks with preference dried fruit, is the Indian meal moth ( Plodia interpunctella ). Other pests that feed on the dried food are grains moths, corn and bacon beetles, rats and mice.
Use of dried food
Dried food can be consumed directly or processed instead of non- dried food in dishes. Therefore it is necessary depending on the recipe, for a few hours to soak the dried food or vegetable especially dried mushrooms in water to supply the moisture removed from him again the food to be dried.
Fruits, mushrooms and herbs can be crushed into powder after desiccating and used as a seasoning or as a base of liquid foods (eg soups, shakes ).
Swell
- Achim Samwald: Drying: Fruits, vegetables, herbs; Ulmer Verlag, 4th edition 2007, ISBN 9,783,800,149,223th