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.
