Packaging Dried foods should be sealed in airtight packages or containers to prevent them from picking up moisture from the air, thus causing them to mold or spoil. There are several options manufacturers use to package the dried food: plastic laminated foil pouches (like Mylar®™), metal and plastic cans, or heavy plastic bags. Most of these are then vacuumed packed to remove as much air as possible. Many may also have oxygen absorber packets added. Some may have a nitrogen gas pumped into the container to replace the oxygen and prevent oxidation and spoilage. Home dried foods are susceptible to insect contamination and moisture absorption and must be properly packaged and stored immediately. First, cool and condition completely. Conditioning is an important safety measure because packaging warm food causes sweating, which could provide enough moisture for mold to grow. Pack foods into clean, dry, insect-proof containers as tightly as possible without crushing (Brennand, 1994). If possible, pack the foods in amounts that can be used after opening the package without requiring further repackaging and storage. Glass jars (preferably dark colored), metal cans, or boxes with tightly fitted lids or moisture- and vapor-resistant freezer cartons make good
shelf life. Foods that are packaged seemingly bone-dry can spoil if moisture is reabsorbed during storage. Check dried foods frequently during storage to see if they are still dry. Glass containers are excellent for storage because any moisture that collects on the inside can be seen easily. Foods affected by moisture, but not spoiled, should be used immediately or re-dried and repackaged. Moldy foods should be discarded (Schmutz and Hoyle, 1999). Properly stored, dried vegetables keep well for 6 to 12 months. Discard all foods that develop off smells or flavors or show signs of mold. All dried vegetables deteriorate to some extent during storage, losing vitamins, flavor, color, and aroma. For this reason, dried vegetables will not retain their appeal indefinitely. Recommended storage time for dried foods range from 4 months to 1 year. Because food quality is affected by heat, the storage temperature helps determine the length of storage; the higher the temperature, the shorter the storage time. Vegetables have about half the shelf life of fruits and can generally be stored for 6 months at 60º F or 3 months at 80º F. (Schmutz, Hoyle, 1999). The sensory shelf life of dehydrated potato flakes packaged in no. 10 cans held at ambient temperatures was found to be 16 years (Neilson et al., 2006).
containers for storing dried foods. Heavy-duty plastic bags are
NUTRITION
acceptable but are not insect and rodent-proof (Schmutz and
Drying, like all methods of preservation, can result in loss of
Hoyle, 1999). To protect from insects and re-absorption of moisture, seal lids onto containers. Wrap the edge where the lid meets the container with a plasticized, pressure-sensitive tape or a clean, 1-inch cloth strip dipped in melted paraffin. Bags may be heat-sealed or closed with twist ties, string or rubber bands. Label containers with the name of the product, date, and method of pretreatment and drying (Kendall et al., 2012). Oxygen absorbers can also be used to remove oxygen from the packages to extend shelf life and minimize off-flavors.
some nutrients. Nutritional changes that occur during drying include (Kendall et al., 2012): • Calorie content: does not change, but is concentrated into a smaller mass as moisture is removed. • Fiber: no change. • Vitamin A: fairly well retained under controlled heat methods. • Vitamin C: mostly destroyed during blanching and drying of vegetables.
STORAGE CONDITIONS & SHELF LIFE Containers of dried vegetables should be stored in a dry, cool, dark place away from furnaces. Low storage temperatures extend the shelf life of dried products. Always store metal cans off the floor, especially bare concrete. Moisture can wick up to cans and encourage rusting. If there is enough space, dried vegetables can also be stored in the freezer to enhance the
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DRIED FOOD STORAGE
• Thiamin, riboflavin, niacin: some loss during blanching but fairly good retention if the water used to rehydrate is also consumed. • Minerals: some may be lost during rehydration if soaking water is not used. Iron is not destroyed by drying.
