Connective Tissue

Fish connective tissue is weak because its collagen contains less structure-reinforcing amino acids than beef collagen does, and because the muscle tissue also serves as an energy store that’s repeatedly built up and broken down, whereas in land animals it is progressively reinforced with age. Meat collagen is tough and must be cooked for some time near the boil to be dissolved into gelatin, but in most fish it dissolves at 120 or 130°F/ 50–55°C, at which point the muscle layers separate into distinct flakes.