User Guide

5
MODEL: RJ43-5-R
PRETREATING
The Enzymes in fruits and vegetables are responsible for the color and flavor changes
that occur while ripening. These changes will continue during dehydration and storage
unless the food item is pretreated. Pretreating works by slowing down enzyme activity.
Blanching is a form of pretreatment which can be used for vegetables. Blanching is a
technique in which you briefly immerse vegetables in boiling water and then immediately
place them into iced water or cold running water to halt the cooking process. Blanching
may also prevent undesirable changes in flavor during storage and improve reconstitution
during cooking.
Many light-colored fruits (especially apples, apricots, peaches, nectarines and pears)
tend to darken during drying and storage. To prevent this darkening, the fruit may be
pretreated by blanching or by a suitable dip. The effectiveness of pretreatment method
varies.
Different dipping methods include:
1) Pineapple or Lemon Juice: A great natural pretreatment used to reduce browning.
a.) Slice fruit directly into juice.
b.) Remove promptly (approximately 2 minutes).
c.) Place on trays.
NOTE: Fruit may also be dipped into honey, spices, lime juice, or orange juice.
2) Sodium Bisulfite: Only use food safe, (USP) grade.
a.) Dissolves 1 teaspoon of sodium bisulfite in one quart of water.
b.) Prepare small amounts of fruit and dip for 2 minutes in the solution. This helps
prevent loss of Vitamin C and maintains a bright color.
NOTE: Sodium Bisulfite may be obtained from a local pharmacy.
3) A solution of table salt.
4) A solution of ascorbic acid or citric acid. Commercial antioxidant mixtures containing
ascorbic acid may also be used, but often are not as effective as pure ascorbic acid.
Fruits may be steam-blanched. However, blanched fruit may turn soft and become
difficult to handle.
Syrup blanching may help retain the color of apples, apricots, figs, nectarines, peaches,
pears and plums. This will result to sweetened candied products.
Fruits with tough skins (grapes, prunes, and small dark plums, cherries, figs and some
berries) may be water-blanched to crack the skin. This will allow moisture inside to
surface more readily during drying.
Before drying pretreated food, remove any excess moisture by placing the food on a
paper towel or a clean cloth. Drying trays should be loaded with a thin layer of food as
directed. If needed, clean cheesecloth can be spread on the trays to prevent food pieces
from sticking or falling through.
The amount of food being dried at one time should not exceed roughly 3/4 of each tray's
surface area and 1/4" thick.
Operating Instructions