How is collagen obtained for use in cosmetics?

Known for its hydrating benefits, the collagen in most cosmetic products is typically extracted from a variety of animal species (birds, beef, pork, fish, rabbit, molluscs, fish, etc.). It comes from different parts of animals, derived from slaughter by-products, such as skin, tendons, cartilage, scales, internal organs, and bones, which are the main sources.

Animal-derived collagen faces religious restrictions and health restrictions, particularly those related to the risk of transmission ofbovine spongiform encephalopathy, or avian flu and foot-and-mouth disease.

Regardless of the method selected, the fresh or frozen raw material is rinsed (at least 3 times) to remove all undesirable compounds (residual blood, fats, flesh scraps, etc.), then dried in a cold electric dryer before being ground.

Acid extraction of collagen, the most commonly used procedure in the industry, requires preliminary treatments of deproteinisation and demineralisation. During deproteinisation, the raw material, previously cleaned, is immersed in a basic solution (sodium hydroxide, calcium hydroxide, etc.), which varies depending on the origin of the extracted tissue, at high concentrations for up to 24 hours at 4°C under agitation. This step allows the removal of non-collagenous proteins to achieve satisfactory yields and a collagen with a high degree of purity without altering its structural integrity.

Depending on the raw material used, the sample can be added to a butyric acid solution to remove excess fat.

The alkaline bath is followed by a water rinse to remove excess basic formula and a filtration process to recover the deproteinised residues. After deproteinisation, the demineralisation stage ensues to eliminate as many minerals as possible. To achieve this, two acids can be used: hydrochloric acid (HCl) and EDTA, and this can last up to 48 hours. The deproteinised, demineralised and neutralised raw material is then added to an acidic formula (acetic acid, citric acid, lactic acid, etc.) and maintained for 24 to 72 hours, depending on the raw material, under constant agitation at 4°C in order to solubilise the non-crosslinked collagen and break certain bonds.

The collagen hydrolysate thus obtained is then subjected to ultrafiltration in order to remove large, undissolved aggregates. This is an advanced filtration method where the liquid is forced at high pressure through a series of membranes/meshes with microscopic openings, to ensure greater product purity and stability, as well as minimise contamination risks. Low molecular weight collagen peptides pass through to the other side, while impurities (traces of heavy metals, etc.) are retained and discarded.

The supernatant that has been collected is then selectively precipitated by the addition of a neutral salt, preferably sodium chloride (NaCl), for at least 12 hours at a low temperature without stirring, before being resuspended in acetic acid. This is followed by the removal of the salt through dialysis using a dialysis bag and the drying of the liquid into a powder form (lyophilisation) by atomisation or spraying.