KSB S4: Appearance Changes
Dehydration
may change the color and/or structure of an apple slice. Examine
an apple slice under a dissecting microscope before, during and
after dehydration. Describe what you observe through sketches
and words. Chemical preservatives are sometimes used ahead of
time to decrease the change in appearance of dried fruit and to
prevent further spoilage. Ascorbic acid, citric acid, lemon juice,
salt water and sodium bisulfite are commonly used in drying foods.
Use a dissecting microscope to make before-and-after comparisons
of the color and structural changes to the apple slices that you
treat with one of the above-mentioned chemical preservatives.
Record the results. Research through experimentation the effects
of chemical preservatives on dehydration.
TOPIC:
Protecting Light-Colored Fruits
Develop
Your Understanding
1. What observations
did you make about the appearance of the slices before and after
dehydration?
2. What observations
did you make about the appearance before and after dehydration
of slices treated with chemical preservatives?
3. What do
you consider the advantages and disadvantages of the use of chemical
preservatives during dehydration?
