On Food and Cooking

Meat pigments. Left: The heme group, a
carbon-ring structure at the center of both
hemoglobin and myoglobin molecules that
holds oxygen for use by the animal body’s
cells. The protein portion of these molecules,
the globin, is a long, folded chain of amino
acids, and is not shown here. Right: Three
different states of the heme group in uncooked
meat. In the absence of oxygen, myoglobin is
purple. Myoglobin that has bound a molecule
of oxygen gas is red. When little oxygen is
available for some time, the iron atom in the
heme group is readily oxidized — robbed of
an electron — and the resulting pigment
molecule is brownish (right).
This connection between exercise and
flavor has been known for a very long time.
Nearly 200 years ago, Brillat-Savarin made