used to crush the tissue. Mashing by hand
leaves large cell aggregates intact; the screens
in food mills and strainers produce smaller
pieces; machine-powered food processor
blades chop very finely, and blender blades,
working in a more confined space, chop and
shear more finely still. Persistent cellulose-
rich fibers can be removed only by passing the
puree through a strainer.
Juices Juices are refined versions of the
puree: they are mainly the fluid contents of
fruit and vegetable cells, made by crushing
the raw food and separating off most of the
solid cell-wall materials. Some of these
materials inevitably end up in the juice — for
example, the pulp in orange juice — and can
cause both desirable and undesirable haziness
and body. Because juicing mixes together the
contents of living cells, including active
enzymes and various reactive and oxygen-
sensitive substances, fresh juices are unstable