Gelatin

Gelatin or gelatine (from Latin: gelatus meaning 'stiff' or 'frozen') is a translucent, colorless, flavorless food ingredient, derived from collagen taken from animal body parts. Brittle when dry and gummy when moist, it is also called hydrolyzed collagen, collagen hydrolysate, gelatine hydrolysate, hydrolyzed gelatine, and collagen peptides. It is commonly used as a gelling agent in food, medications, drug and vitamin capsules, photographic films and papers, and cosmetics. Substances containing gelatin or functioning in a similar way are called gelatinous substances. Gelatin is an irreversibly hydrolyzed form of collagen, wherein the hydrolysis reduces protein fibrils into smaller peptides; depending on the physical and chemical methods of denaturation, the molecular weight of the peptides falls within a broad range. Gelatin is in gelatin desserts; most gummy candy and marshmallows; and ice creams, dips, and yogurts. Gelatin for cooking comes as powder, granules, and sheets. Instant types can be added to the food as they are; others must soak in water beforehand. Hydrolysis results in the reduction of collagen protein fibrils of about 300,000 Da into smaller peptides. Depending upon the process of hydrolysis, peptides will have broad molecular weight ranges associated with physical and chemical methods of denaturation. The amino acid content of hydrolyzed collagen is the same as collagen. Hydrolyzed collagen contains 19 amino acids, predominantly glycine, proline and hydroxyproline, which together represent around 50% of the total amino acid content. Hydrolyzed collagen contains 8 out of 9 essential amino acids, including glycine and arginine—two amino-acid precursors necessary for the biosynthesis of creatine. It contains no tryptophan and is deficient in isoleucine, threonine, and methionine. The bioavailability of hydrolyzed collagen in mice was demonstrated in a 1999 study; orally administered 14C hydrolyzed collagen was digested and more than 90% absorbed within 6 hours, with measurable accumulation in cartilage and skin.A 2005 study in humans found hydrolyzed collagen absorbed as small peptides in the blood. Ingestion of hydrolyzed collagen may affect the skin by increasing the density of collagen fibrils and fibroblasts, thereby stimulating collagen production. It has been suggested, based on mouse and in vitro studies, that hydrolyzed collagen peptides have chemotactic properties on fibroblasts or an influence on growth of fibroblasts. Some clinical studies report that the oral ingestion of hydrolyzed collagen decreases joint pain, those with the most severe symptoms showing the most benefit. Beneficial action is likely due to hydrolyzed collagen accumulation in the cartilage and stimulated production of collagen by the chondrocytes, the cells of cartilage. Several studies have shown that a daily intake of hydrolyzed collagen increases bone mass density in rats. It seems that hydrolyzed collagen peptides stimulated differentiation and osteoblasts activity – the cells that build bone – over that of osteoclasts (cells that destroy bone).