The other major macronutrient type, carbohydrate, does not feature prominently in seafoods, and will not be further discussed here. Carbohydrate is virtually absent in significant amounts from all bony fish commonly eaten. The higher lipid level in such fish is the reason the are often referred to a fatty fish, oily fish or oil-rich fish. The major proteins in fish are actin and myosin, which combine in muscle to form actomyosin.
Albumins are also present.
The amino acid composition of fish protein is such that it can provide the sole source of protein for humans, as a consequence of the presence and extent of the essential amino acids it contains. The actual amino acid pattern is comparable to that of other proteins of high Biological Value, such as beef, egg or milk protein. The amount of connective tissue in fish and shellfish muscle is relatively low. It softens and dissolves more readily when heated compared to the connective tissue of land animals, and is readily hydrolysed by digestive enzymes . It is therefore easy to chew and digest when cooked.