In the past, due to its light weight and nutritional content, freeze dried food sustained soldiers during the the Vietnam War. Today, it's a common staple for space travel. The LoveToKnow Organic website says that freeze dried foods taste and look good, have a longer shelf life and are easier to carry and store than fresh food. Some popular freeze dried foods include vegetables, fruits, meat, coffee, juice, snacks, desserts and dinner entrees.
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Freeze dried foods have been around since the ancient Peruvian Incas, according to LoveToKnow Organic. Incas stored their crops in the Machu Picchu mountains, and the low air pressure combined with high-altitude, cold air vaporized the water in the crops. Today, the process of removing water from frozen foods is called "lyophilization." The freeze drying process was commercialized after World War II.
The Emergency Essentials website describes the freeze drying process as one that creates a variety of easy-to-prepare foods. First, fresh foods are flash frozen, and a vacuum chamber removes their moisture content by applying low heat that causes the ice to evaporate without melting. The freeze dried food weighs about 90 percent less than before the freeze drying process.
LoveToKnow Organic says that freeze dried foods retain the nutrients and vitamins they contained when first picked. Honeyville reports that freeze dried foods help consumers meet their recommended five servings of fruits and vegetables per day, as freeze dried foods are convenient to store and consume. In particular, reports Honeyville, freeze dried strawberries, blueberries, raspberries, corn, carrots and peas provide additional nutritional benefits such as fiber, antioxidants, phytonutrients, B vitamins and vitamin A, folic acid, iron, folate, thiamin, pantothenic acid and vitamin C.
The American Institute for Cancer Research reports that fresh fruits' antioxidant phytochemicals are retained after the fruits are freeze dried, and that those phytochemicals are able to reach the bloodstream.
Dehydrated Versus Freeze Dried
Wilderness Dining explains that freeze dried foods differ from dehydrated foods in several ways. Freeze dried foods are made using low heat, which causes only minimal damage to a food's original aroma, texture and taste. The process, however, is time consuming and the machinery required is expensive. On the other hand, says Wilderness Dining, dehydrated food's moisture is removed through evaporation, a lower-cost method that works better for foods like peppers, tomatoes, and onions.
The Survival Acres website says that typical dehydrated foods are single-ingredient foods such as rice or beans, and they require cooking and seasoning. Freeze dried foods often contain several or more seasonings and ingredients and are precooked. Once open, freeze dried foods need only be heated in hot water.
The shelf life for freeze dried food varies by food type. For example, Survival Acres says the company Mountain House claims its freeze dried food has a 30-year shelf life, and Alpine Aire says its freeze dried foods last 15 years.
Key to preserving the food safely is the way you store it. Survival Acres says to keep freeze dried food out of direct sunlight, at a constant-temperature cool or dark place, and away from areas that could flood. An additional benefit to freeze dried food, says the company, comes from its concentrated size, allowing a one year's supply of food to fit in an area 2 feet by 3 feet in diameter, with the packages stacked about 5 feet high. Be Prepared adds that freeze dried foods' light weights -- about 75 to 90 percent lighter than their original weight -- make them ideal for packing in survival or emergency kits.