Shellfish, protein content

Shellfish, cholesterol content, 461 Silver, protein staining, 171-172,180,182, 199, 202, 204-205 Simple lipids, extraction of, 432 Single-substrate reaction, 333 Site-specific lipid oxidation of emulsions, 627... 

Lysine The average content of lysine in proteins is 7%. High amounts of lysine are found in most animal proteins meat, eggs and milk proteins commonly contain 7-9% of lysine, fish and shellfish proteins contain 10-11% of lysine. In contrast, vegetable proteins, such as proteins of cereals (especially gliadins, but not... 

Both finfish and shellfish are highly valuable sources of proteins in human nutrition. The protein content of fish flesh, in contrast to the fat content, is highly constant, independent of seasonal variations caused by the feeding and reproductive cycles, and shows only small differences among species. Table 4 summarizes the approximate protein contents of the... 

Table VIII shows the average values for amino acids in fish proteins. Block and Bolling (1945) emphasize the fact that muscle proteins from a wide variety of species show little if any significant differences in their content of aromatic amino acids. . . the relative constancy in the basic amino acids in all types of muscle, animal, fish, or crustacean, is noteworthy. The authors use crustacean as synonymous with shellfish. Hence, their generalizations are meant to include oysters and clams.

Most protein-rich foods, including red meat and poultry as well as fish, contain cholesterol. However, almost all types of fish and shellfish contain well under 100 mg of cholesterol per 100 g, and many of the leaner types of fish typically have 40-60 mg of cholesterol in each 100 g of edible muscle. It is known that most shellfish also contain less than 100 mg of cholesterol per 100 g. Shrimp contain somewhat higher amounts of cholesterol, over 150 mg per 100 g, and squid is the only fish product with a significantly elevated cholesterol content, which averages 300 mg per 100 g portion. Fish roe, caviar, internal organs of fishes (such as livers), the tomalley of lobsters, and the hepatopancreas of crabs can contain high amounts of cholesterol. 

Table 5 Content of essential amino-acids in fish and shellfish (g per lOOg of protein) ...

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