Freeze drying, also known as cryodesiccation, is a type of dehydration process used to preserve perishable foods such as fruits and vegetables. It's not as simple as regular dehydration, because it involves flash-freezing first. Freeze-dried fruit contains only 3 percent of the water that fresh varieties do, but it contains comparable levels of many nutrients. Freeze-dried fruit is a healthy alternative for you and your family, especially when fresh varieties are out of season.
Freeze Drying
Freeze drying food dates back to the ancient Incas of the Andes, who found that they could expose their food to freezing night temperatures and let the dry heat of the sun evaporate the moisture, which preserved their food for long periods of time. This process was eventually commercialized during the World War II era in efforts to preserve blood serum without the need for refrigeration. Soon after, pharmaceuticals and food were freeze dried. According to the "Dictionary of Food Science and Technology," preservation of food is possible with this method because the lack of water inhibits the action of microorganisms and enzymes that would normally spoil it. If you seal freeze-dried fruit to prevent reabsorption of moisture, you can store it at room temperature without spoilage for many years.
Freeze-Dried Vs. Dehydrated
To dehydrate food, you slowly remove the water through use of heat. Ancient people used sun drying, smoking or wind drying to achieve desired results. Freeze drying causes less damage to food than traditional dehydration, takes far less time and doesn't usually shrink or toughen the food; freeze-dried fruit has the same shape and size as fresh fruit, but with 97 percent less water and much less weight, according to Gordon Wardlaw, author of "Contemporary Nutrition: Functional Approach." Freeze-dried fruit maintains most of its flavor, aroma and nutrients. You can eat freeze-dried fruit directly or rehydrate it before consumption.
Health Benefits of Freeze-Dried Fruit
The health benefits of freeze-dried fruit are close to those of fresh varieties, with some important distinctions. First, you are missing the water content; hydration is an important benefit from eating fresh fruit, especially juicy varieties such as watermelon and oranges. Freeze-dried fruit contains lower levels of vitamins, especially water-soluble varieties such as vitamin C and some B vitamins. According to "Nancy Clark's Sports Nutrition Guidebook," freeze-dried fruit contains between 60 percent and 80 percent of the nutrients that fresh varieties contain, although vitamin C levels may be dramatically less. However, freeze-dried fruit contains the same level of minerals, fiber, pectin and antioxidants that fresh varieties do. Freeze-dried fruit doesn't have any sugar or preservatives added, unlike some dried fruits.
Other Benefits
Freeze-dried fruit is convenient to carry because it is light and can endure high temperatures. As a result, freeze-dried fruit is a popular snack with hikers and campers, and even has gone into orbit with astronauts. Unlike regular dehydrated foods, you can eat freeze-dried fruit as is or soak it in hot water for a few minutes to quickly rehydrate. Freeze-dried fruit is more expensive than fresh and dehydrated varieties, but it may become more economical if you are the type to forget about your fruit in the fridge and have to frequently throw it out.
References
- "Dictionary of Food Science and Technology: 2nd Edition"; International Food Information Service; 2009
- "Contemporary Nutrition: Functional Approach"; Gordon M. Wardlaw; 2009
- "Nancy Clark's Sports Nutrition Guidebook: 4th Edition"; Nancy Clark; 2008
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