Pale Translucence Most of the muscle in most raw fish is white or off-white and delicately translucent compared to raw beef or pork, whose cells are surrounded by more light-scattering connective tissue and fat cells Especially fatty portions of fish, such as salmon and tuna bellies, look distinctly milky compared to flesh from just a few inches away The translucence of fish muscle is turned into opacity by cooking treatments that cause the muscle proteins to unfold and bond to each other into large, light-scattering masses Both heat and marination in acid unfold proteins and turn fish flesh opaque Red Tunas The meaty color of certain tunas is caused by the oxygen-storing pigment myoglobin (p 132), which these fish need for their nonstop, high-velocity life (p 201) Fish myoglobin is especially prone to being oxidized to brownish metmyoglobin, especially at freezer temperatures down to – 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 ... 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... 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... 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