The best way to explain food dehydration is to look at body dehydration. At one time or another, we all have experienced dehydration. For instance, after exercising and perspiring heavily, someone has probably told you to be sure to drink plenty of fluids or your body would dehydrate. When you exercise the body becomes hot and begins to perspire, this heat causes the moisture to be drawn out of your body through the pores in your skin. When it reaches the skin’s surface, it is evaporated by the passing air currents. This leaves your body with a liquid deficiency, therefore, it can be said to be dehydrated. For dehydration to take place, as you will note, two basic conditions must be present:
- Heat – enough to draw out moisture, and
- Air circulation – to carry the moisture off and evaporate it. To dehydrate most effectively, the air should be able to absorb the released moisture.
What is Food Dehydration?
All food is composed of solids (starch, proteins, fiber, etc.) and a significant amount of water. Basically food dehydration, commonly known as food drying is the process of removing water from produce.
Food dehydration, like body dehydration, depends on these two conditions. But, unlike body dehydration (which can be harmful), food dehydration or food drying is done with a specific purpose in mind: to preserve the food from spoiling in the most natural way possible.
That is, food dehydration can be defined as a process of inactivating enzymes or removing water (moisture) from food to a point at which bacteria and other spoilage microorganisms are inhibited from growing. Properly dehydrated or dried food can last for months without refrigeration.
There are other ways of preserving foods, freezing and canning, being the most popular. Unlike these other preservation methods, dehydration does not kill or cause deterioration of enzymes.
Enzymes are the chemical properties found in all living things that control the growth cycle, causing them to mature and/or ripen. Think of this, when you harvest a green tomato from the garden, you will notice that over a day or 2 or even 3, the tomato starts turning red, you are now witnessing enzymes in action. What this also shows, however, is that the action continues after the food is picked, eventually causing it to over ripen and decay. Dehydration suspends the action of these enzymes, putting them into a state of inactive or suspended animation until the food is re-hydrated or water is added.
Advantages of Food Dehydration
- Remove a major portion of water and you reduce spoilage and increase the food's storage life.
- Dried foods generally have little, or no, specialised storage requirement.
- Moisture removal reduces weight and makes food easier to transport.
- Drying allows you to preserve food grown in your garden so that you can enjoy it throughout the year.