Minnesota Extension Service INFO-U Script Copyright (c) 1994 Minnesota Extension Service, University of Minnesota. All rights reserved. _________________________________________________________________ SCRIPT NUMBER: 766-R SCRIPT TITLE: Drying Food SUBJECT AREA: Safe Home food Preservation AUTHOR: Bill Schafer, University of Minnesota SPECIALIST REVIEWER: Shirley Barber AGENT CONTACT: Shirley Barber LAST REVIEW DATE: April 1992 NEXT REVIEW DATE: April 1994 DRYING FOOD Drying is a method of food preservation that is simple, safe and easy to learn. Drying also creates new food products such as fruit leather, banana chips, pumpkin seeds and beef jerky. Drying removes the moisture from the food so bacteria, yeasts and molds can't grow. Drying also slows down the action of enzymes, which cause food to ripen and eventually spoil. Because drying removes moisture, the food shrinks, and becomes lighter in weight. When the food is ready for use, water is added, and the food returns to its original shape. Certain foods can be dried in the sun, in an oven, or in a food dehydrator by using the right combination of warmth, low humidity and air currents. In drying, a warm temperature allows the moisture to evaporate. Air currents speed up drying by moving the surrounding moist air away from the food. Low humidity allows moisture to move from the food to the air. Drying food is a slow process. Sun drying takes three to five days while solar drying takes one or two days. It is difficult to do sundrying or solar drying in Minnesota because humidity is often too high. In a dehydrator, it will take 6 or more hours to dry foods, and in your oven, it will take 8 or more hours. Drying time depends on type of food, thickness, and type of drying method you're using. Don't be tempted to speed up the drying time by turning up the oven. You will cook the food on the outside before it dries on the inside. This is called case hardening. The food may appear dry on the outside but may be wet on the inside. Moisture left in the food will cause it to mold. To prepare food to dry: Select fresh, good quality fruits and vegetables. Trim away inedible and damaged portions. Cut into halves, strips, or slices that dry readily. Strips should be 1/8 to 1/4 inch thick. Vegetables need to be blanched. When you blanch vegetables, you heat them enough to neutralize the natural enzymes. If you omit this step, or inadequately blanch vegetables, they will have poor flavor and color. You can blanch in steam or in hot water. Water blanching is quicker, but may leach out some color and nutrients. You can pretreat most fruits by dipping them in antioxidant such as citric/ascorbic acid mixtures. After foods are dried, allow 30 minutes to one hour cooling time to prevent condensation. However, too long a cooling period allows moisture from the air to re-enter the food. Proper storage prevents insects and rodents from eating the food. It also keeps moisture out and saves valuable nutrients. Glass jars, metal cans or boxes with tight fitting lids, or vapor-proof freezer cartons make good containers. Heavy duty plastic bags with press together seals are acceptable, but are not insect or rodent proof. Using new lids on glass jars prevents insect contamination, but it is not necessary to heat process the jars. If new lids are available, use a pressure sensitive tape or a clean one-inch strip of cloth that is still warm after being dipped in paraffin. These methods keep insects out. Dried foods will keep from four months, to one year, but proper storage is very important. Cool, dry, dark areas are best. For best quality, the storage temperature should not go over 60 degrees. Although it is not necessary to store dried food in a refrigerator or freezer, except for meat jerkies, this does provide a low temperature which extends the shelf life. After packaging, check containers within seven to ten days to see if any moisture is present. If you see any moisture, food must be redried at 140 degrees to 160 degrees. If food is moldy, discard the it. - More - Page 3 Title: Drying Food Script #: 766 Dried fruits can be eaten as nutritious snacks, or they can be soaked for one to two hours and used in favorite recipes. Some vegetables can be eaten dried as tasty vegetable chips for dips. Most vegetables are refreshed with water before use. The water can be added back to vegetables in one of three ways. Soak in tap water for one to two hours, using about two cups of water for each cup of food; you can use boiling water, which speeds up the soaking period; or you can add dried vegetables directly to soups or stews without soaking. # # # _________________________________________________________________ This item is copyrighted. 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