cooking water or sprinkled on the food can
help with both aims: its citric acid binds up
metal ions. Cooking red cabbage with acidic
apples or vinegar keeps it from turning
purple; dispersing baking soda evenly in
batters, and using as little as possible to keep
the batter slightly acidic, will keep blueberries
from turning green.
Creating Color from Tannins On rare and
wonderful occasions, cooking can actually
create anthocyanins: in fact, it transforms
touch into color! Colorless quince slices
cooked in a sugar syrup lose their astringency
and develop a ruby-like color and
translucency. Quinces and certain varieties of
pear are especially rich in phenolic chemicals,
including aggregates (proanthocyanidins) of
from 2 to 20 anthocyanin-like subunits. The
aggregates are the right size to cross-link and
coagulate proteins, so they feel astringent in
our mouth. When these fruits are cooked for a