<P> 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 . 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 . </P>
<P> 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 . 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 . </P>
what part of the pig is used to make gelatin
what part of the pig is used to make gelatin
skin
skin