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_Brief description

Gelatin is obtained by the hydrolysis of collagen which is the principal protein found in skin and bones. The precursor for gelatin is collagen. Collagen is the major structural protein found in the skin and bones of all animals. The collagen molecule consists of 3 individual polypeptide chains (alpha chains) which are wound around one another in a triple helix confirmation. This triple helix is stabilized by hydrogen bonds between collagen molecules, which happens as the animal ages. A collagen molecule of three alpha chains would measure 2700Aº in length (0.27 microns) and 14Aº in diameter. Each alpha chain has approximately 1050 amino acids connected together. There are twenty different amino acids in each alpha chain, and for each animal type of gelatin, these amino acids are in a specific repeated pattern. Glycine, which represents a third of the amino acids content, is in repeated sequence with two other amino acids. This might be represented as glycine-x-y. It is not unusual for x to be proline and y to be a hydroxyproline residue.

Commercial extraction of gelatin depends upon both dissolving and hydrolyzing the denatured skin. The gelatin may retain some covalent bonds between alpha chains, which would entail multiples of the single alpha chain length of 95,000 daltons. There are also major proportions of shorter chain polypeptide in the gelatin, as the chain is cleaved in the extraction process. This is not necessarily a problem, as the end product may not need very high molecular fractions in order to accomplish the specific application. Coils of amino acids are joined together by peptide bonds. The predominant amino acid sequence is Gly-Pro-Hyp . As a result, gelatin contains relatively high levels of these amino acids: glycine (Gly) 27%; proline (Pro) 10-18%; and hydroxy proline (Hyp) 7-15% .Other significant amino acids include: alanine (Ala) 8%;arginine (Arg) 8%; aspartic acid (Asp) 6%; and glutamic acid (Glu)12%. Percent of water will vary between 6 to 9% Ash content is 0.1 to 3.25% Gelatin swells and absorbs 5-10 times its weight of water to form a gel in aqueous solutions between 30-35°C. Gelatin is used as a stabilizer, the foam should not collapse before the product gelling can take place. Gelatin is used as a foaming agent by reducing surface tension it enables the introduction of air into a material. Gelatin is often combined with other gelling agents to obtain a particular texture or characteristic. Other gelling agents include agar, pectin, gum arabic, modified starch, carrageenan, gellan gum, alginates, etc.

How to make
There are Two different base processes used a) Alkali process: The ossein or skin is immersed in a (alkali) lime bath for a number of weeks at room temperature. b) Acid process: The ossein or skin is immersed in an acid bath for a short period of time, sometimes just for 1 day. A rinsing process removes the alkali or acid, and the pH level is adjusted to the desired level. The product is cooked & processed at controlled temperatures to extract the gelatin, as hot water dissolves the gelatin contained in the base. The gelatin that is extracted from the base is processed and filtered to remove all impurities, traces of grease and other substances that have coagulated at high temperatures. This process produces a clear gelatin solution. The solutions are further concentrated to level of between 30 & 40%. The concentrated solutions are sterilized at 140º C and abruptly dropped to a low temperature 5º C to make the solution into a jelly. Dry the jelly in a dryer. The gelatin will be concentrated to level around 87%. The extractions are crushed and screened to obtain the desired granular size end product. No two bathes will be identical. The various extractions will be blended and grouped to give a consistent commercial batch quality that will comply with the specification.

Quality evaluation
there are constant lab tests made to assure the quality & consistency of the product based in: Viscosity (mps) Gel strength (bloom) Ph There are some other parameters like ash, fat, foam, etc…specifics for some industrial applications.

Furniture, bank notes, books, picture frames, matches, sandpaper, sellotape, cork and musical instruments are just a few traditional products that could only come into existence thanks partly to technical gelatine. photographic paper and film, shampoo and facial crème, in deluxe packaging and detergents, in paper for inkjet printers and in modern pet food. Gelatin is added to electroplating baths to control the deposition rate. Similarly, gelatin functions as a zinc brightener by controlling the crystallization of zinc during deposit.

How to use gelatin

How to keep gelatin:
Dry gelatin (13% water), kept dry, can keep for years

How to prepare gelatin aqueous solutions:
There are two ways to dissolve gelatin into water:

  • 1. Add gelatin into cold water and mix slowly. Wait some hours to the solution blow up. Dissolve and homogenize heated in a double boiler at 50ºC.
  • 2. Add gelatin into hot water(60-70ºC) in a big tank with heating and mixing system. Mix slowly.

Keep gel solution
We have to control pH (between 5 & 8), Temperature(not higher than 60ºC) and cleanliness.