On Food and Cooking

fats and oils than in water. Bottom right:
Cyanidin, a blue pigment in the anthocyanin
family. Thanks to their several hydroxyl (OH)
groups, anthocyanins are water-soluble, and
readily leak out of boiled vegetables.
Discoloration: Enzymatic Browning Many
fruits and vegetables — for example apples,
bananas, mushrooms, potatoes — quickly
develop a brown, red, or gray discoloration
when cut or bruised. This discoloration is
caused by three chemical ingredients: 1- and
2-ring phenolic compounds, certain plant
enzymes, and oxygen. In the intact fruit or
vegetable, the phenolic compounds are kept in
the storage vacuole, the enzymes in the
surrounding cytoplasm. When the cell
structure is damaged and phenolics are mixed
with enzymes and oxygen, the enzymes
oxidize the phenolics, forming molecules that
eventually react with each other and bond
together into light-absorbing clusters. This
system is one of the plant’s chemical