Gelatin

Gelatin (also gelatine) is a translucent brittle solid, colorless or slightly yellow, nearly tasteless and odorless, that is created by prolonged boiling of animal connective tissue.

It is a protein product derived through partial hydrolysis of the collagen extracted from skin, bones, cartilage, ligaments, etc. The natural bonds between individual collagen strands are broken down into a form that rearranges more easily. Gelatin melts when heated, and solidifies when cooled again. Together with water it forms a semi-solid colloidal gel.

On a commercial scale, gelatin is made from by-products of the meat and leather industry, mainly pork skins, pork and cattle bones, or split cattle hides. Contrary to popular belief, horns and hooves are not commonly used. The raw materials are prepared by different curing, acid, and alkali processes, sometimes over many weeks, to extract the dried collagen hydrolysate. The worldwide production amounts to ca. 250,000 t per year.

Household gelatin comes in the form of sheets, granules, or powder. Instant types can be added to the food as is, others need to be soaked in water beforehand. Special kinds of gelatin are made only from kosher animals, or from fish, to comply with Jewish kashrut laws. Vegetarians may substitute similar products obtained from vegetable sources, such as agar.

Due to the mad cow disease (BSE) and its link to the Creutzfeldt-Jakob disease, there has been much concern about using gelatin derived from possibly infected animal parts.

Uses

Probably best known from cooking as a jellying agent, different types and grades of gelatin are used in a wide range of food and non-food products:

Common examples of foods that contain gelatin are trifles, jelly, aspic, marshmallows, or gummy bears. Gelatin may be used as a stabilizer, thickener, or texturizer in foods such as ice cream, cream cheese, fat-reduced margarine, etc.

Gelatin makes up the shells of pharmaceutical capsules. It can be used as carrier, coating, or separating agent for other substances. Cosmetics may contain a variant of gelatin under the name of "hydrolyzed collagen". Gelatin is closely related to bone glue, and is used as a binder in match heads, or sandpaper.

It is used to hold silver halide crystals in an emulsion in almost all photographic films and photographic papers. Despite some efforts, no suitable substitutes with the stability of gelatin have been found.

Gelatin is used for the clarification of juices and beverages such as apple juice or vinegar. Isinglass, from the swim bladders of fish, is still used as a fining agent for wine and beer. Beside hartshorn jelly, from deer antlers, it is one of the oldest sources of gelatin.

See also: gelatin dessert