Buying Tuna Steaks
Why are some fresh tuna steaks light in color and others are much darker, and how can I tell if they are fresh by looking at them?
Ellen Wax, Portland, OR
Steve Cook replies:
There are two main reasons for the color difference in tuna steaks. One is the species. Tuna steaks are almost always cut from yellowfin, bigeye, or blue fin tuna, which are generally considered the choicest species. Yellowfin is the lightest in color, a rosy red. The bigeye has a deeper red color, while the bluefin is a very deep red to purple. The pale albacore tuna is generally not cut into steaks but is reserved for canning.
The second reason for color difference in tuna steaks is the fat content. A tuna steak with a higher fat content will have a lighter color than a leaner one of the same species. The fat content of the steak varies depending on which part of the fish the steak came from. The tuna belly is fattier than the back, so a steak from the belly would be lighter in color than one cut from the back.
The fat content also varies depending on the time of year. In the fall, tuna caught off the northern Atlantic coast of the United States are higher in fat because they have been up in the northern waters all summer putting on weight to prepare for their migration south. However, after their migration in early winter to warmer waters, they are leaner.
The lighter- colored, fattier tuna steaks have more flavor than the lean, although this flavor difference is more easily detected when the tuna is eaten raw (it has a sweeter taste) j it's less noticeable when eaten cooked.
When buying tuna steaks, the shininess of the fish is more important than the variations in color. A shiny, brightcolored steak is a sign of freshness. A steak with a dull shine, whatever the color, is a sign that it has passed optimum freshness.
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