Gelatin is a translucent, colorless, odorless, and nearly tasteless substance that is made by prolonged boiling of skin, cartilage and bones from animals. It’s made primarily from the stuff meat industries have left over – like pork skins and cattle bones.
On a commercial scale, gelatin is made from by-products of the meat and leather industry. Gelatin is derived from pork skins, pork, horses, and cattle bones, or split cattle hides.
The raw materials are prepared by different curing, acid, and alkali processes which are employed to extract the dried collagen hydrolysate.
These processes may take up to several weeks, and differences in such processes have great effects on the properties of the final gelatin products. Gelatin is an irreversibly hydrolysed form of collagen, and is classified as a ”foodstuff”. Common examples of foods that contain gelatin are gelatin desserts, trifles, aspic, marshmallows, candy corn, and confections such as Peeps, gummy bears, fruit snacks, and jelly babies.
Gelatin may be used as a stabilizer, thickener, or texturizer in foods such as yogurt, cream cheese, and margarine; it is used, as well, in fat-reduced foods to simulate the mouthfeel of fat and to create volume without adding calories.
Gelatin is used for the clarification of juices, such as apple juice, and of 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 (hence the name “hartshorn”), isinglass was one of the oldest sources of gelatin. If the physical material that will be used in production is derived from bones, dilute acid solutions are used to remove calcium and similar salts.
Hot water or several solvents may be used for de-greasing. Maximum fat content of the material should not exceed 1% before the main extraction step. If the raw material is hides and skin, size reduction, washing, removing hair from the hides, and de-greasing are the most important pretreatments used to make the hides and skins ready for the main extraction step.
Raw material preparation for extraction is done by three different methods: acid, alkali, and enzymatic treatments. Acid treatment is especially suitable for less fully crosslinked materials such as pig skin collagen. Pig skin collagen is less complex than the collagen found in bovine hides.
Acid treatment is faster than alkali treatment and normally requires 10 to 48 hours. Alkali treatment is suitable for more complex collagen, e.g., the collagen found in bovine hides. This process requires longer time, normally several weeks. The purpose of the alkali treatment is to destroy certain chemical crosslinkages still present in collagen.
The gelatin obtained from acid treated raw material has been called type-A gelatin, and the gelatin obtained from alkali treated raw material is referred to as type-B gelatin.
Enzymatic treatments used for preparing raw material for the main extraction step are relatively new