In this week’s article, I’d like to talk about freeze dried food vs. dehydrated food. A lot of people keep asking me what’s the difference. Both methods of preservation remove the liquid and moisture from the food and both can be reconstituted with water, but the similarities end there. A lot of factors come into play – like how it’s made, shelf life, taste, and nutrition. Let’s talk about these points one by one and distinguish the differences.
Freeze Dried Food Vs. Dehydrated Food – How It’s Made
We’ve talked extensively about Freeze Dried Food – How It’s Made in our previous article. We’ll definitely touch on that later. But first, let’s discuss how dehydrated food and how it’s made in order to get a better understanding about their differences.
Dehydration is the process of removing water from a substance. The extraction of moisture inhibits the growth if microorganisms which causes food to spoil. Dehydration is one of the oldest methods of food preservation and was used by prehistoric peoples in sun-drying seeds. The North American Indians preserved meat by sun-drying slices, the Chinese dried eggs, and the Japanese dried fish and rice.
Dehydrated food is made by applying heat to the desired food item, resulting in 90% of the substance’s water being lost to evaporation. It’s this lack of moisture that enables dehydrated foods to be stored for long periods of time. Storage life is typically 1-10 years if stored at a stable temperature of 21 degrees Celsius and possibly longer if stored at cooler temperatures.
Lyophilization or freeze drying, on the other hand, is mainly a two-step process of rapid freezing and subsequent dehydration. Food is fast-frozen by placing the item between two hollow plates that contain a refrigerant liquid in a tightly-sealed chamber. While the food is being frozen, a high-powered pump creates a vacuum in the chamber. Then the refrigerant liquid in the hollow plates is replaced with warm gas, which converts the ice in the food directly into vapor. This process removes 98% of water from the food which allows it to be stored 25 years or more under stable and cool conditions.
There’s a lot of science and technology that goes behind the making of freeze dried food. This is one of the reasons why it is more expensive than dehydrated food. On the other hand, it’s a small price to pay to make sure you have emergency food anytime, anywhere, today, tomorrow, and 25 years from now.
Freeze Dried Food Vs. Dehydrated Food – Taste and Nutrition
Dehydrated food retains 60% of its nutrients. The nutrient loss for commercially-dried foods varies between 30 – 80% for vitamin C and 10 – 50% for vitamin A. The amount of loss is dependent on many factors, including storage time, drying temperature, and dry time. Commercially dried fruit is usually treated with preservatives and sweeteners, which changes the nutrition content.
A lot of commercially dehydrated fruit is pre-treated with sulfur dioxide or sodium sulfite to keep it from getting brown during the drying process, which preserves vitamin A and vitamin C in the fruit, but can get rid of thiamine. Heat in the dehydrator as well as exposure to air can lower fruit’s vitamin C content. Boiling fruit before dehydrating it can help preserve carotene, which is broken down by the body into vitamin A, but does lower the vitamin C content. Soaking or boiling before dehydrating can also cause some minor loss of minerals.
After dehydration, food receives a chewy texture, however they do not lose a considerable amount of flavor. Flavors are not completely changed, but many feel dehydrated foods are slightly less flavorful than foods that have been freeze dried.
As for freeze drying , 97% of its nutrients are retained in the food. Flash freezing preserves the cell structure, nutrients, shape, and color of the food. Fiber remains intact, as do antioxidants and phytochemicals, which are chemical compounds that may provide protective health benefits. Fruits hold up to 90% of their original nutritional content. This means you can still get your daily dose of vitamin A and C.
Freeze dried foods are made using low heat, which causes only minimal damage to a food’s original aroma, texture and taste. Since the food remains frozen during the process, the food’s cell structures do not change and the products generally retain the original taste. 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.
Freeze Dried Food Vs. Dehydrated Food – No Contest
We’ve outlined the differences between freeze dried food and dehydrated food. On paper, I’d have to say it’s no contest. Freeze dried food not only lasts longer, it tastes better, and more nutritious than dehydrated food. Of course, there’s nothing wrong if you want to use dehydrated food and store it as your emergency food. But, wouldn’t you feel more secure knowing that your emergency food is tasty, full of nutrients, and as fresh as it was packed 25 years ago? I think that’s an easy question to answer.