Gelatin and collagen

Collagen is the most abundant protein in mammals as it constitutes the main fraction of structural proteins in connective tissue. Gelatin, obtained by partial hydrolysis of collagen, is one of the most versatile biopolymers and has numerous applications in food, confectionery, pharmaceutical/medical, cosmetic, and technical products. This is also reflected by the approximately 450,000 metric tonnes of gelatin produced annually worldwide. Gelatin has been investigated and studied by scientists at least since the early 20th century but has been applied in foods even before this. The properties of the manufactured gelatins depend on the origin of the parent collagen and the severity of the extraction procedures. Today, gelatins are mainly produced from bovine and porcine sources, but gelatin may also be extracted from fish and poultry. This chapter focuses mainly on the manufacturing of mammalian gelatin, and the connection between the chemical compositions and the structure-function relationship of gelatins from mammalian sources as well as from cold and warmwater fish species.