Collagen is composed of three polypeptide chains to form a triple helix structure, that is, each of the three polypeptide chains rotates left-handed to form a left-handed helix structure, and then occludes each other with hydrogen bonds to form a firm right-handed super helix structure (unique to collagen).

Three peptide chains of type I collagen, including two α(I) Chain, 1 piece α (II) Chain. There are only minor differences in the amino acid sequences between the α(Ⅰ) and α(Ⅱ) chains.

Type I collagen is mainly distributed in fish skin, fish scale, porcine, bovine skin, bone and other tissues. One of the most significant characteristics of type I collagen in fish collagen is its low thermal stability and obvious absorption effect.

Collagen type Ⅱ is composed of three identical α chains, namely [α I (Ⅱ)]3, which is rich in hydroxylysine and is the main collagen in cartilage. Collagen type II is produced by chondrocytes.

Collagen and collagen polypeptides are different. Collagen molecules are mainly hydrolyzed to form collagen polypeptides with small relative molecular weight. Due to the unique triple helix structure of collagen, its properties are very stable, and the general processing temperature and short time heating cannot decompose it, which makes it difficult to digest and absorb, and is not easy to be fully utilized by the human body.

The hydrolyzed collagen polypeptide has high absorption and utilization rate, which can promote the absorption of other proteins in food. Collagen polypeptides are extremely soluble in water, acid and alkali resistant, high temperature resistant, strong water absorption, etc. They are widely used in the field of food and cosmetics.

The triple helix structure of collagen