Collagen is a biopolymer, the main component of animal connective tissue, and the most abundant and widely distributed functional protein in mammals, accounting for 25% ~ 30% of the total in protein, and even more than 80% in some organisms. Animal tissues from livestock and poultry are the main way for people to obtain natural collagen and collagen peptides.
The collagen content of aquatic animals is higher than that of terrestrial animals, such as silver carp, bighead carp and grass carp. The protein content is 25.9%, 23.6% and 29.8% respectively, which are all higher than the protein content of their corresponding fish: 17.8%, 15.3% and10. The content of collagen in fish skin can exceed 80% of total protein, which is much higher than other parts of fish.
It is reported that the collagen in the skin of real snapper accounts for 80.5% of the crude protein, while that of eel is as high as 87.3%. Such a high content means a high yield, such as 42.5% for small tuna; Japanese sea bass 40.7%; Fragrant fish 53.6%; Yellow sea snapper 40.1%; Bamboo pod fish 43.5% (all calculated by dry weight).
Extended data
Collagen is generally white and transparent powder, and its molecules are slender and rod-shaped, and its relative molecular weight is about 2kD-300 KD. Collagen has strong ductility, is insoluble in cold water, dilute acid and dilute alkali solution, and has good water retention and emulsification.
Collagen is not easy to be hydrolyzed by ordinary protease, but it can be broken by animal collagenase, and the broken fragments automatically denature and can be hydrolyzed by ordinary protease. When the environmental pH is lower than neutral, the denaturation temperature of collagen is 40 ~ 465438 0℃, and when the environmental pH is acidic, the denaturation temperature is 38~39℃.
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