sugar ribose and the sulfur-containing amino
acid cysteine, probably from the myoglobin
pigment, which produces an aroma compound
that’s also typical of cooked beef.
Tuna has been the subject of
connoisseurship at least since classical times.
Pliny tells us that the Romans prized the fatty
belly (the modern Italian ventresca) and neck
the most, as do the Japanese today. Tuna
belly, or toro, can have ten times the fat
content of the back muscle on the same fish,
and commands a large premium for its
velvety texture. Because the bluefin and
bigeye tunas live longest, grow largest, and
prefer deep, cold waters, they accumulate
more fat for fuel and insulation than other
species, and their meat can fetch hundreds of
dollars per pound.
The Tuna Family
These major oceangoing tuna species are
found worldwide.