What You Need

• The only obstacle you may run into is whether your oven will adjust to the appropriate temperature. You will need to be able to maintain an internal temperature of 135 to 145 degrees Fahrenheit, with 140 being your target. Get a pot large enough to fit the foods into and fill it with two inches of water. Make a mixture of one part lemon juice and two parts ice water and place it in a bowl. You'll need a tray to lay your prepared food on, a knife to prepare the food, and something to prop the oven door open with. Something heat-resistant is best, such as a rolling pin.
  
  

Food Prep

• Use a knife to slice the fruits and vegetables into the desired shapes. For example, are you making banana chips? Slice in small circles. Dried pineapple? Large rings work nicely. Be careful to remove any unripe, hard or dark spots from the food by trimming them away. If you wouldn't eat it fresh, don't expect drying it to make it any better.
  
  When preparing vegetables bring a pot of water to a boil and drop them in for about two minutes. This should adequately remove any impurities and kill any food borne organisms that may be on the food. The blanching should leave them a nice color, but the drying process could change that, so give them a quick dip in the bowl of lemon juice and ice water solution. The Vitamin C in the lemon juice acts as a natural color stabilizer and will make everything look as nice as it tastes, and the cold water will stop the food from cooking further. For fruit, a quick rinse, slice and dip in the lemon juice solution is all that is required.
  
  

Dehydrating

• Preheat your oven to 145 degrees and place the prepared foods on a tray. When the temperature is reached, place the tray of food on the rack and prop the door of the oven open slightly (2 inches or so) with a rolling pin, a rolled up oven mitt, or whatever you choose as your prop. You want to be at 140 degrees, so setting the temp of the oven at 145 and having the door cracked should get you close. Use a thermometer to regularly check the actual temperature, making sure it is between 135 and 145 degrees at all times. You do not want to "cook" the food, which will drastically affect the taste. Rotating the tray and moving around the foods will help make the drying process more even, as the hot and cool spots in ovens vary. About once an hour will be sufficient.
  
  

Time Requirements

• The time requirements vary for different fruits and vegetables, but often it takes between 8 and 12 hours to completely dehydrate these foods. Often it will take more than 24 hours depending on the size and type of fruits or vegetables used. You will know that they are getting close when 80 to 90 percent of the original weight of the prepared food has evaporated. You can test this with a food scale if you wish. See the resources section for approximate drying times. A way to test doneness, according to University of Illinois at Urbana-Champaign's College of Agriculture, is to hit the pieces with a hammer to see if they shatter. If they do, they are completely dehydrated. The exceptions to this rule are mushrooms, green peppers and squash, which become tough and leathery.
  
  

Storage

• Be sure to cool the dehydrated foods thoroughly as any warm pieces may sweat in a storage container. If you choose, after cooling, you may reheat the oven to 180 degrees and place the food back in the oven for 15 minutes with the door closed to "pasteurize" the finished product. Then after cooling again thoroughly, store your snacks in airtight containers such as zip bags to keep until you are ready to enjoy them.