Avoid bruised or rotten celery. Celery cells contain chemicals called furocoumarins (pso-
ralens) that may turn carcinogenic when the cell membranes are damaged and the furocou-
marins are exposed to light. Bruised or rotting celery may contain up to a hundred times the
psoralens in fresh celery.
Storing This Food
Handle celery carefully to avoid damaging the stalks and releasing furocoumarins.
Refrigerate celery in plastic bags or in the vegetable crisper to keep them moist and
crisp. They will stay fresh for about a week.
Preparing This Food
Rinse celery under cold running water to remove all sand and dirt. Cut off the leaves, blanch
them, dry them thoroughly, and rub them through a sieve or food mill. The dry powder can
be used to season salt or frozen for later use in soups or stews.
What Happens When You Cook This Food
When you cook celery the green flesh will soften as the pectin inside its cells dissolves in
water, but the virtually indestructible cellulose and lignin “strings” on the ribs will stay stiff.
If you don’t like the strings, pull them off before you cook the celery.
Cooking also changes the color of celery. Chlorophyll, the pigment that makes green
vegetables green, is very sensitive to acids. When you heat celery, the chlorophyll in its stalks
reacts chemically with acids in the celery or in the cooking water to form pheophytin, which
is brown. The pheophytin will turn the celery olive-drab or, if the stalks have a lot of yellow
carotene, bronze.
You can prevent this natural chemical reaction and keep the celery green by cooking it
so quickly that there is no time for the chlorophyll to react with the acids, or by cooking it
in lots of water (which will dilute the acids), or by cooking it with the lid off the pot so that
the volatile acids can float off into the air.
How Other Kinds of Processing Affect This Food
Medical Uses and/or Benefits
Celery