22ºF/–30ºC; tuna must be frozen well below
this to keep its color. During cooking, fish
myoglobins denature and turn gray-brown at
around the same temperature as beef
myoglobin, between 140 and 160ºF/60 and
70ºC. Because they are often present in small
quantities, their color change can be masked
by the general milkiness caused when all the
other cell proteins unfold and bond to each
other. This is why fish with distinctly pink
raw flesh (albacore tuna, mahimahi) will turn
as white as any white fish when cooked.
Orange-Pink Salmons and Trouts The
characteristic color of the salmons is due to a
chemical relative of the carotene pigment that
colors carrots. This compound, astaxanthin,
comes from the salmons’ small crustacean
prey, which create it from the beta-carotene
they obtain from algae. Many fish store
astaxanthin in their skin and ovaries, but only
the salmon family stores it in muscle. Because