WebMD Public Information from the Department of Health and Human Services
Drying is the oldest method of preserving food. The first European settlers in America often ate dried corn, apple, currants, grapes and meat. Sun drying of food was an easy way to prolong the life of food, but this form of dried food was different from what is available today. In different climates, the food dried differently because complete sun drying is dependent on very particular weather conditions. Drying eliminates moisture from the food resulting in a longer food life. Organisms that make food spoil require moisture to survive, so foods that have been completely dried have the longest life.
The methods of drying food, particularly fruits and vegetables, have become more sophisticated over time. The three most common methods used today are briefly described below:
Solar: Solar dehydration of food requires 3 to 5 consecutive days of 95 degrees or above and low humidity. This climate is found only in limited areas in the United States.
Oven: Foods are dried using a household kitchen oven. This method can be expensive as many hours are normally required to dry food. Oven dried foods are often times darker and more brittle than foods dried by other methods. This method is often suggested for first time dryers, as very little new equipment is required for this method.
Dehydrator: This type of drying produces the highest quality product. An electric dehydrator may be purchased and various sizes and levels of quality are generally available.
Dried fruits and vegetables are high in fiber and carbohydrates and low in fat. However, dried foods are more calorically dense than their fresh counterparts. The recommended serving size for dried fruits and vegetables is half that of fresh.
Vitamin C is one nutrient that is destroyed by heat. Pretreating food with citrus juice can help increase the vitamin C content of the dried food.
For drying at home, select ripe fruits and vegetables for drying. Bruised fruit may be used if those areas are removed before drying. Do not use any food with mold on it for drying. Peel and slice food into 1/8 to 1/2 inch slices. The higher the water content, the larger the slice should be because the more it will shrink in drying.