F.A.Q.

Proteins are organic compounds present in both animal and vegetal organisms and are composed of long chains of amino acids linked together by amide bonds; these bonds are called peptide bonds and form between the amine and carboxyl group of the amino acids with the release of a molecule of water.

Amino acids differ from each other in the presence of a specific side chain that can have a nonpolar, polar, acid or basic nature and gives every single amino acids particular chemical properties.

Proteins differ from each other in the different presence, frequency and sequence in which the various amino acids can link together; amino acids side chains can form bonds with each other making the polypeptide chain assume a particular spatial conformation or can associate with other side chains of another polypeptide chain. Protein amino acid chains structural features and also those of the relative hydrolysates in general depend on the chemical-physical conditions of the aqueous solution they are in (pH, presence of ions, temperature, concentration, presence of some organic compounds) and a change in equilibrium conditions can easily denature them (eg loss of solubility).

Protein solubility is mainly affected by the molecular weight; at the same physicochemical conditions, the decrease of the molecular weight generally causes an increase of protein solubility.

For native proteins we mean proteins isolated from vegetal or animal sources that maintain their original molecular weight and the amino acids chemical characteristics.

A hydrolyzed protein is a protein derived from native proteins and is composed of lower molecular weight peptides that have a greater solubility than the relative native proteins from which they derive.

The hydrolysis of proteins can be carried out by adding strong basic or acid substances or via enzymatic means; chemical hydrolysis can be mild or strong and can cause destruction of the amino acids chains, denaturation of some amino acids side chains and destruction of some amino acids. Enzymatic hydrolysis makes use of specific proteases capable of breaking up the amino acid chains in specific sites; this kind of hydrolysis doesn’t cause amino acids side chains denaturation and amino acids destruction.

Hence we can refer to a protein hydrolysate ONLY as amino acids chains with different molecular weight that can be in aqueous solution or in a powder form; on the market there may be found substances formed by molecules of proteinic origin condensed with other molecules such as cationic compounds or fatty acids. This kind of substances are obtained through synthesis processes and form molecules with totally different properties than the ones of the proteins from which they originate.

During cleansing, the outer skin layer comes in contact with surfactants capable of removing the dirt but also part of the natural hydrolipidic component of the stratum corneum, causing a temporary and partial depletion of lipid and protein substance; over time this can lead to alteration of the normal skin balance and impairment of the barrier function with consequences that can range from stratum corneum hydration decrease to dermatitis in more sensitive skins.

Proteins utilization in combination with surfactants has proven to be an effective protection against the aggressive action of these substances without compromising their washing and foaming efficacy; the protective action is carried out both through the formation of bonds between protein and surfactant monomeric units, that are those most able to penetrate skin membranes, and through the formation of numerous weak bonds with epidermal proteins that get covered by a protective colloidal film.

Proteins applied to skin form weak but numerous bonds with epidermal proteins, creating a thin, non-occlusive protective colloidal layer: the higher protein molecular weight, the greater the film-forming effect on skin; instead, lower molecular weight hydrolysates, rich in small peptides and amino acids, can have a buffering and humectant effect and be of useful application in products for skins that are deficient in these components.

Some proteins can also have an anti-radical activity and help to preserve the integrity of other skin components, as during UV radiation exposure.