juicy), it should have a rich pineapple aroma, and you should hear a solid “thunk” when you
tap a finger against the side. While the pineapple’s shell generally loses chlorophyll and turns
more golden as the fruit ripens, some varieties of pineapple have more chlorophyll and stay
green longer than others, so the color of the shell is not a reliable guide to ripeness.
Storing This Food
Store pineapples either at room temperature or in the refrigerator. Neither will have any
effect on the sweetness of the fruit. Fruits and vegetables get sweeter after they are picked
by converting stored starches to sugars. Since the pineapple has no stored starch and gets its
sugar from its leaves, it is as sweet as it ever will be on the day it is picked. It will get softer
while stored, though, as its pectic enzymes break down pectins in its cell walls.
Preparing This Food
To sweeten and soften fresh pineapple, peel and slice the fruit (or cut it into chunks), sprinkle
it with sugar, and chill it in the refrigerator. The sugar and water on the pineapple’s surface
is a denser solution than the liquid inside the pineapple’s cells. As a result liquid flows out
of the cells. Without liquid to hold them rigid, the cell walls will collapse inward and the
pineapple will be softer. This physical phenomenon—the flow of liquids across a membrane
from a less dense to a more dense environment—is called osmosis.
What Happens When You Cook This Food
As you cook pineapple, the pectic substances in its cell walls dissolve and the pineapple
softens.
If you add fresh pineapple to gelatin, the bromelain will digest the proteins in the
gelatin and the dish won’t “set.” However, bromelain only works at a temperature between
140°F and 170°F; it is destroyed by boiling. For the maximum effect in stewing, set the heat
at simmer. To add fresh pineapple to a gelatin mold, boil the fruit first.
How Other Kinds of Processing Affect This Food
Drying. Drying concentrates the calories and nutrients in pineapple. Fresh pineapple may
be treated with a sulfur compound such as sulfur dioxide to protect its vitamin C and keep
it from darkening as it dries. In people sensitive to sulfites, these compounds may provoke
serious allergic reactions, including potentially fatal anaphylactic shock.
Juice. Since 2000, following several deaths attributed to unpasteurized apple juice contami-
nated with E. coli O157:H7, the FDA has required that all juices sold in the United States be
pasteurized to inactivate harmful organisms such as bacteria and mold.
Pineapple