Food Storage Tips

Nutrients and Vitamins

In any type of food processing, from boiling and canning to simply cutting with a knife, some degree of nutrients are going to be lost. The unique technique of food dehydration, where gentle temperatures and long drying time tenderly remove moisture, is ideal for nutrient preservation in foods.

Compared to canning and freezing, dehydration is the superior food preservation method in regard to conservation of nutrients. The United States Department of Agriculture indicates that on average freezing foods for food storage yields 40-60% nutrient loss, while canning can create a whopping 60-80% loss. Home food dehydration, however, produces only 3-5% nutrient loss on average!

The secret is in the temperature. The extremely low temperatures used in freezing cause cells to lyse (break open), spilling out nutrients. On the other end of the spectrum, very high heats in canning can destroy nutrients and cells as well. Dehydration uses a long drying time in order to keep a temperature that is only gently elevated.

To key to optimal nutrient preservation is to remove key food-degrading agents: oxygen, light, and heat.

Oxidation is a reaction that alters the chemical structure of items, from sliced apples (browning) to sheets of iron metal (rusting). This reaction is often fueled by oxygen. The alteration of chemical structure by oxygen results in a loss of nutrients over time and will change the taste and appearance of the food. For long-term food storage, therefore, it is optimal to vacuum seal items to remove oxygen and add an oxygen pack to remove residual oxygen.

Light and heat both contribute to the spoilage of food and destruction of nutrients. Many vitamins, including vitamins A and C, are photosensitive, meaning they are destroyed by long-term exposure to light. For optimal long-term food storage, therefore, it is best to store items in a cool and dark place, such as a basement, that is not damp. You may also double bag your vacuum bags inside Mylar bags, which have a tough and reflective outer coating to keep out light and heat.

Specific Nutrients in Dehydration:

Calories:

Dehydrating has no effect on calorie content. However, dehydrated foods have more calories per weight because removing the water shrinks the food and makes it lighter without removing any calories. The condensed product is consequently more calorie dense. A calorie is a measure of the amount of energy in food.

Carbohydrates and other Sugars:

Dehydration has no effect on the total carbohydrate or sugar content in food. However, dehydrated fruit will be sweeter than non-dried fruit, since the removal of the water concentrates the sugar in the fruit into a smaller volume and weight. The removal of the water also makes the fruit lighter, meaning that a person eating the same amount in weight of dried fruit as a piece of fresh fruit would be consuming more calories and sugar. This can be good for hikers or athletes who may need a quick energy boost from a lightweight and portable food, but it can be problematic for dieters.

Fiber:

Dehydrating food has no effect on total fiber content. Fiber is a plant material that aids with digestion.

Minerals:

Minerals, such as iron, are not affected by food dehydration. However, some minerals may be lost during slicing of the food. In canning, foods are exposed to liquid long term, and therefore are more subject to mineral drain off.

Proteins:

Dehydrating food has no effect on total protein content. Protein consumption is important for proper development and growth.

Vitamin A:

Beta-carotene, which is converted to vitamin A in the body, is destroyed by contact with air. Beta-carotene is the substance in certain foods, such as carrots, that provides their brilliant orange color. You can witness the loss of vitamin A by simply leaving carrots out in the open. The vitamin A will begin to deplete, and the color of the carrots will fade. Luckily, this process can be prevented through blanching of items. The process of blanching before dehydrating some items will increases the quantity of beta-carotene, and change its structure slightly to prevent its loss. For an experiment, dehydrate some uncooked carrots and some blanched carrots and set them side-by-side. The blanched dehydrated carrots will not only appear much brighter orange, but over time their color will not fade. Vitamin A is important for vision, growth, and development.

Vitamin B:

B vitamins are water-soluble and are therefore sometimes lost in water drain off when slicing foods or blanching. Prolonged exposure to water, such as in canning, will increase the loss of vitamin B. Although vitamin B is water soluble, it will not evaporate along with the water when you dehydrate, and so dehydration is a method of processing is gentle toward vitamin B loss. B vitamins are important for metabolism and many cellular functions in the body.

Vitamin C:

Vitamin C is a delicate nutrient that is easily lost in all forms of food processing and handling. The reason is that vitamin C is degraded by both air and light. The best way to prevent this vitamin loss is by removing the air, using vacuum sealing and oxygen absorbers, and removing the light by Mylar bag storage, or storage away from light. In addition, spraying some items prior to dehydrating will add a blast of vitamin C.

Vitamin C deficiency can causes a collagen disorder known as scurvy. Although we do not hear of scurvy much these days in a developed country, it still occurs. The best way to prevent scurvy is simply to eat a nourishing and well-rounded diet, with occasional consumption of fruits and vegetables. A healthy diet that consists of dehydrated and fresh foods poses no threat of scurvy.

Still, we recommend keeping vitamin C tablets in your food storage as well just in case. The high concentration of vitamin C in these tablets allows them to have a long shelf life if they are stored properly. Just as with your foods, you should remove the vitamin C tablets from the bottle and vacuum seal with an oxygen pack, and store away from light. As vitamin C naturally degrades, which is inevitable under any situation, its chemical structure changes making it inactive. Luckily, this altered form of vitamin C is not dangerous to consume, and therefore your vitamin C tabs will only lose potency over time, and not expire.

Prepackaging dehydrated soups

If you are making prepackaged soups for easy cooking, or to give away to friends and family as gifts, simply add all spices and ingredients directly to the mix and then vacuum seal. The only things you must keep separate are the bouillon cubes (because they contain moisture), cornstarch, and flour (because it will absorb moisture). Place each of these items in their own little separate sealed bags or zip lock bags. Place all of the little bags right into the large vacuum bag containing the rest of your dehydrated ingredients.