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Gelatin is a popular gelling agent. Gelatin is obtained from bones, skins and tissue of animals. Usually by-products from a slaughterhouse of cows, pigs and fish is used. Since 2001 the bones of cows may not be used anymore for feed and food in the EU. These bones may only be used for gelatin for technical applications.
Gelatin is water soluble and digestible and is a gel that is strong, flexible and transparent.
Reception, examination, sorting, cutting en purificationThe bones, tissues and/or skins of cows and pigs are delivered from the slaughterhouse. The rotten and unusable parts are removed during the examination. Afterwards, the bone parts are sorted by size. After sorting there are 3 fractions. The A and B fraction are stored to be further processed to gelatin. The C fraction consists of too small particles. This fraction cannot be used for the production of gelatin. In order to make skins and tissues more workable they are cut in pieces with a diameter of several centimeters. Afterwards, the undesired parts of bones, tissues and skins are hosed with a powerful jet of water.
soaking the parts in hot water. The fat melts and can be sucked from or skimmed off the water surface. Subsequently, the low fat pieces are dried and roasted by heating them at a temperature of 100°C for 30 minutes.
This is reached by washing the pieces several times with acid (4% hydrochloric acid with a PH below 1.5). In this process, the calcium carbonates are dissolved from the pieces. These calcium carbonates are further processed to dicalcium phosphate. After the acid purification the material is called oseine.
After the purification with acid the oseine is neutralized by washing it several times with water. Afterwards it is washed several times with a sodium hydroxide or a potassium hypochlorite solution to kill micro-organisms. It is washed a several times in order to neutralize it and to rinse it from remainders. The total purification process with acid and lye takes 12 to 20 hours.
milk the collagen can melt during the extraction. After the treatment with calcium carbonates it is crudely purified on a vibrating filter.
extraction or melting. The bones, tissues and skins are boiled in water. The water that is added has a starting temperature of 55°C. Later in the process water of 95°C is added. The higher the temperature is the lower the gelling capacity of the gelatin. Therefore, it is extracted three times at increasing temperatures. By lightly acidifying the solution the collagen more rapidly converts into gelatin, which increases the efficiency. Acidifying can happen by adding sulphuric acid. After all the collagen has been concerted into gelatin, after about 15 hours, it has a gelatin solution with 5% gelatin.
boiling process it is now neutralized. It can be neutralized by adding sodium hydroxide. Sodium hydroxide splits in the water into sodium ions and hydroxide. The hydroxide together with the hydrogen forms water.
vacuum. The gelatin solution is concentrated from a concentration of 5% to 22%. Next it is sterilized in order to kill all micro-organisms and thus to guarantee the storage life. Sterilization at a temperature of 140°C for 4 seconds gives the desired result.
sweeteners. During this phase of the process the additions can be mixed in the (still warm) gelatin. For the production of jelly sugar, sugar is mixed with gelatin powder.
air over it. The sterile air is necessary to prevent infection.