Gelatin & it's uses

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Gelatin or animal jelly, foodstuff obtained from connective tissue

(found in hoofs, bones, tendons, ligaments, and cartilage) of

vertebrate animals by the action of boiling water or dilute acid. It

is largely composed of denatured collagen, a protein particularly rich

in the amino acids proline and hydroxyproline. The process of

manufacture is a complex one that involves removing foreign

substances, boiling the material (usually in distilled water in

aluminum vessels to prevent contamination), and purifying it of all

chemicals used in freeing the gelatin from the connective tissues. The

final product in its purest form is brittle, transparent, colorless,

tasteless, and odorless and has the distinguishing property of

dissolving in hot water and congealing when cold. In contact with cold

water it takes up from 5 to 10 times its own weight and swells to an

elastic, transparent mass. Gelatin, being readily digested and

absorbed, is a good food for children and invalids. It is important in

fine cookery as a vehicle for other materials, in the form of jellied

soups, molded meats and salads, and frozen desserts. Preparations of

it are used in the home manufacture of jam, jellies, and preserves to

ensure jellification of fruit juices. It is used in the drying and

preserving of fruits and meats, in the glazing of coffee, and in the

preparation of powdered milk and other powdered foods. Bakeries use it

in making meringues, eclairs, and other delicacies. In confectionery

making it is used as the basis of taffy, nougat, marshmallows, and

fondant. Ice cream manufacture employs it to maintain a permanent

emulsion of other ingredients and thus to give body to the finished

product. In scientific processes gelatin is widely employed, being

used in electrotyping, photography, waterproofing, and dyeing, and in

coating microscopic slides. It is used as a culture medium for

bacteriological research and also to make coatings for pills and

capsules, for court plaster, and for some surgical dressings. It

affords a base for ointments and pastes, such as toothpaste; it is an

emulsifying agent useful in making liquid combinations and various

sprays. In its less pure forms gelatin is known as glue and size.

Vegetable gelatin, or agar, is derived from East Indian seaweeds.