what part of the pig is used to make gelatin
Gelatin Gelatin is a mixture of peptides and proteins produced by partial hydrolysis of collagen extracted from the skin, bones, and connective tissues of animals such as domesticated cattle, chicken, pigs, and fish. During hydrolysis, the natural molecular bonds between individual collagen strands are broken down into a form that rearranges more easily. Its chemical composition is, in many aspects, closely similar to that of its parent collagen.[2] Photographic and pharmaceutical grades of gelatin generally are sourced from cattle bones and pig skin. Gelatin has proline, hydroxyproline and glycine in its polypeptide chain. Glycine is responsible for close packing of the chains. Presence of proline restricts the conformation. This is important for gelation properties of gelatin.[3][not in citation given]