Gelatin

Gelatin is a protein substance derived from collagen, a natural protein present in the tendons, ligaments, and tissues of mammals. It is produced by boiling the connective tissues, bones and skins of animals, usually cows and pigs. Gelatin's ability to form strong, transparent gels and flexible films that are easily digested, soluble in hot water, and capable of forming a positive binding action have made it a valuable commodity in food processing, pharmaceuticals, photography, and paper production.

As a foodstuff, gelatin is the basis for jellied desserts; used in the preservation of fruit and meat, and to make powdered milk, merinque, taffy, marshmallow, and fondant. It is also used to clarify beer and wine. Gelatin's industrial applications include medicine capsules, photographic plate coatings, and dying and tanning supplies.

Background

Until the mid-nineteenth century, making gelatin was a laborious task. Calves' feet were loaded into a large kettle that was then placed over a fire. The feet were boiled for several hours after which the liquid was strained and the bones were discarded. After setting for 24 hours, a layer of fat would rise to the top. This was skimmed off and discarded. Sweeteners and or flavorings were added to the liquid and it was poured into molds and allowed again to set.

By the 1840s, however, some producers were grinding the set gelatin into a fine powder or cutting it into sheets. One of them was Charles B. Knox, a salesman from Johnston, New York, who hit on the idea of making gelatin more convenient after watching his wife Rose make it in their kitchen. Knox packaged dried sheets of gelatin and then hired salesmen to travel door-to-door to show women how to add liquid to the sheets and use it to make aspics, molds, and desserts. In 1896, Rose Knox published Dainty Desserts, a book of recipes using Knox gelatin.

The first patent for a gelatin dessert was issued in 1845 to industrialist and inventor Peter Cooper. Cooper had already made a name for himself as the inventor of the Tom Thumb steam engine. He had also made a fortune in the manufacture of glue, a process similar to that for making gelatin.

In 1897, Pearl B. Wait, a carpenter and cough medicine manufacturer, developed a fruit-flavored gelatin. His wife, May Davis Wait, named his product Jell-O. The new product was not immediately popular and Wait sold the rights to the process to Orator Francis Woodward, owner of the Genesee Food Company, for $450. Sales continued to limp along until 1902 when an aggressive advertising campaign in Ladies Home Journal magazine generated enormous interest. Sales jumped to $250,000.

The use of gelatin in food preparation increased six-fold in the 40-year period from 1936-1976. Today, 400 million packages of Jello-O are produced each year. Over a million packages are purchased or eaten each day.

In the field of photography, gelatin was introduced in the late 1870s as a substitute for wet collodion. It was used to coat dry photographic plates, marking the beginning of modern photographic methods. Gelatin's use in the manufacture of medicinal capsules occurred in the twentieth century.

Raw Materials

Animal bones, skins, and tissue are obtained from slaughterhouses. Gelatin processing plants are usually located nearby so that these animal byproducts can be quickly processed.

Acids and alkalines such as caustic lime or sodium carbonate are used to extract minerals and bacteria from the animal parts. They are either produced in the food processing plant or purchased from outside vendors.

Sweeteners, flavorings, and colorings are added in the preparation of food gelatin. These can be in liquid or powdered forms and are purchased from outside vendors.

The Manufacturing
Process

Inspection and cutting

• 1 When the animal parts arrive at the food processing plant, they are inspected for quality. Rotted parts are discarded. Then, the bones, tissues, and skins are loaded into chopping machines that cut the parts into small pieces of about Sin (12.7cm) in diameter.

Degreasing and roasting

• 2 The animal parts are passed under high-pressure water sprays to wash away debris. They are then degreased by soaking them in hot water to reduce the fat content to about 2%. A conveyer belt moves the degreased bones and skins to an industrial dryer where they are roasted for approximately 30 minutes at about 200° F (100° C).

Acid and akaline treatment

• 3 The animal parts are soaked in vats of lime or some other type of acid or akali for approximately five days. This process removes most of the minerals and bacteria and facilitates the release of collagen. The acid wash is typically a 4% hydrochloric acid with a pH of less than 1.5. The alkaline wash is a potassium or sodium carbonate with a pH above 7.

Boiling

• 4 The pieces of bone, tissue, and skin are loaded into large aluminum extractors and boiled in distilled water. A tube running from the extractor allows workers to draw off the liquid that now contains gelatin. The liquid is sterilized by flash-heating it to about 375° F (140° C) for approximately four seconds.

Evaporating and grinding

• 5 From the extractor, the liquid is piped through filters to separate out bits of bone, tissue or skin that are still attached. From the filters, the liquid is piped into evaporators, machines that separate the liquid from the solid gelatin. The liquid is piped out and discarded. The gelatin is passed through machines that press it into sheets. Depending on its final application, the gelatin sheets are passed through a grinder that reduces them to a fine powder.

Flavoring and coloring

• 6 If the gelatin is to be used by the food industry, sweeteners, flavorings, and colorings may be added at this point. Pre-set amounts of these additives are thoroughly mixed into the powdered gelatin.

Packaging

The packaging process is automated, with preset amounts of gelatin poured into overhead funnels through which the gelatin flows down into bags made of either polypropylene or multi-ply paper. The bags are then vacuumed sealed.

Quality Control

Gelatin manufacturers must adhere to stringent national and international food processing requirements. These regulations include but are not limited to cleanliness of the plant, equipment and employees; and allowable percentages of additives, flavorings, and colorings.

Automated and computerized technologies allow the processors to preset and monitor ingredient amounts, time and temperature, acidity and alkalinity, and flow levels. Valves are installed along pipelines to allow for continuous sampling of the product.

Gelatin is processed to varying "bloom" values that measure the gel strength or firmness. The desired strength corresponds to the manner in which the gelatin will be used. The bloom value is technically measured and monitored throughout the production process.

The Future

Since 1986 when the presence of bovine spongiform encephalopathy (BSE), also known as mad cow disease, was reported in Great Britain, there has been much concern about the processing of beef bones for the production of gelatin. In 1989, the United States Food and Drug Administration (FDA) banned the importation of cattle from the Department of Agriculture's list of of BSE-designated countries. However, a 1994 FDA ruling allowed the continued importation of bones and tissues for the production of pharmaceutical grade gelatin.

By 1997, however, the FDA held hearings to reconsider its decision. After interviewing gelatin processors, the agency found that while gelatin has not been implicated in the spread of BSE, officials are not convinced that the manufacturing processing is extracting all possible agents that are responsible for the disease. It was generally agreed that beef sources carry more of a risk than those from pork, that bones carry a higher risk than skins, and that alkaline processing is more effective than the acid-extraction method. These findings will certainly affect the gelatin-processing industry in the next century.

Where to Learn More

Books

Harvey Lang, Jenifer, ed. Larousse Gastronomique. New York: Crown Publishers, 1988, reprinted 1998.

Periodicals

Marwick, Charles. "BSE sets agenda for imported gelatin." Journal of American Medical Association (June 4, 1997): 1,659.

Other

Leiner Davis Gelatin. http://www.gelatin.com/ (June 29, 1999).

Kraft Foods. http://www.kraftfoods.com/ (June 29, 1999).

Sterling Gelatin. http://www.sterlinggelatin.com (June 29, 1999).

—MaryMcNulty

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.

gel·a·tin / ˈjelətn/ (also chiefly dated gel·a·tine ) • n. a virtually colorless and tasteless water-soluble protein prepared from collagen and used in food preparation as the basis of jellies, in photographic processes, and in glue. ∎  (usu. blasting gelatin) a high explosive consisting chiefly of a gel of nitroglycerine with added cellulose nitrate.

gelatin(e) A colourless or pale yellow water-soluble protein obtained by boiling collagen with water and evaporating the solution. It swells when water is added and dissolves in hot water to form a solution that sets to a gel on cooling. It is used in bacteriology for preparing culture media, in pharmacy for preparing capsules and suppositories, and in jellies and other foodstuffs.

ge·lat·i·nous / jəˈlatn-əs/ • adj. having a jellylike consistency: a sweet, gelatinous drink. ∎  of or like the protein gelatin: tooth enamel is coated with a gelatinous layer of protein. DERIVATIVES: ge·lat·i·nous·ly adv.

gelatin (jel-ă-tin) n. a jelly-like substance formed when tendons, ligaments, etc. containing collagen are boiled in water. Gelatin has been used in medicine as a source of dietary protein, in pharmacy for the manufacture of capsules and suppositories, and in bacteriology for preparing culture media.

gelatin Colourless or yellowish protein obtained from collagen in animal cartilage and bones. It is used in photographic film emulsions, capsules for medicines, as a culture medium for bacteria, and in foodstuffs such as jellies.

gelatin(e) XIX. — F. gélatine — It. gelatina, f. gelata JELLY; see -INE5.
So gelatinous XVIII. — F. gélatineux.

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