On Food and Cooking

are made up of a framework of cellulose fibers
embedded in a mass of amorphous materials,
including the pectins (left). When cooked in
boiling water, the cellulose fibers remain
intact, but the amorphous materials are partly
extracted into fluids from within the cells,
thus weakening the walls (right) and
tenderizing the vegetable or fruit.
Green Chlorophylls The earth is painted
green with chlorophylls, the molecules that
harvest solar energy and funnel it into the
photosynthetic system that converts it into
sugar molecules. Chlorophyll a is bright blue-
green, chlorophyll b a more muted olive color.
The a form dominates the b by 3 to 1 in most
leaves, but the balance is evener in plants that
grow in the shade, and in aging tissues, where
the a form is degraded faster. The
chlorophylls are concentrated in cell bodies
called chloroplasts, where they’re embedded
in the many folds of a membrane along with
the other molecules of the photosynthetic