[article]
| Titre : |
Amino acid-based surfactants : more than just 'natural' ! |
| Type de document : |
texte imprimé |
| Auteurs : |
Alexander T. Wagner, Auteur |
| Année de publication : |
2020 |
| Article en page(s) : |
p. 92-96 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Acides aminés Les acides aminés (ou aminoacides) sont une classe de composés chimiques possédant deux groupes fonctionnels : à la fois un groupe carboxyle –COOH et un groupe amine –NH2. Parmi ceux-ci, les acides α-aminés se définissent par le fait que leur groupe amine est lié à l'atome de carbone adjacent au groupe acide carboxylique (le carbone α), ce qui leur confère la structure générique H2N–CHR–COOH, où R représente la chaîne latérale, qui identifie l'acide α-aminé.
Les acides α-aminés jouent un rôle fondamental en biochimie comme constituants élémentaires des protéines : ils polymérisent en formant des liaisons peptidiques qui aboutissent à de longues chaînes macromoléculaires appelées peptides.
Formulation (Génie chimique)
Gels -- Emploi en cosmétologie
Huiles et graisses
Hygiène
Produits nettoyants
shampooings
Surfactants
Visage -- Soins et hygiène
|
| Index. décimale : |
668.5 Parfums et cosmétiques |
| Résumé : |
Amino acids are key components of the human metabolism : Glutamate, for instance, is the most important substance in the brain to transport information from one nerve cell to another. It is a neurotransmitter.
Additionally, amino acids can be linked together in different combinations to create shorter (peptides) and longer (proteins) chains. Both fulfil a variety of different vital functions in the human body : Collagen, for instance, is the most frequently occurring protein in the human body. It is composed of three intertwined chains (triple helix) to lend structure to connective tissue. Simply for spatial arrangement reasons in this protein the smallest amino acid, glycine, is the main component.
The water solubility of amino acids also makes them an attractive choice for the hydrophilic part of surfactants. When an amino acid is linked with a triglyceridederived fatty acid (e. g. from coconut oil), surfactants (N-acyl derivatives, "amino acid surfactants") exclusively based on natural components are created. When the amino acid is produced via a fermentation process starting from glucose or its derivatives, the surfactants even are completely composed of renewable raw materials (e. g. cocoyl glutamate). Those surfactants are an ideal choice for natural cosmetic applications.
Contrary to expectations, the development of amino acid surfactants is not a result of the current trend towards ‘green’ surfactants. The first examples were patented in the 1930s. Already at that time one candidate, a derivative of sarcosine, was introduced to the market. The original idea behind this development was to create surfactants alternative to soaps to overcome their drawbacks (precipitation in pH-neutral aqueous solutions, sensitivity to water hardness). The 'trick' is to insert a suitable spacer between the hydrophobic part and the carboxylate group. By the way, in the 1930s also another solution was found : To introduce a sulfo-group and to "block" or replace the carboxylic group of fatty acids (e. g. acyl isethionates and fatty alcohol sulfates).
The attractiveness of amino acid surfactants for cosmetic applications is additionally based on two other aspects : At first, they are proven mild and well foaming surfactants. Secondly, they are excellent biodegradable. The linkage between the hydrophobic and the hydrophilic part of the surfactant is an amide bond. This type of bondage is frequently ‘used’ by nature (e.g. in peptides and proteins) and can therefore easily be cleaved by nature´s enzymes. |
| Note de contenu : |
- Acyl sarcosinates and acyl glycinates : unequal siblings
- Acyl glutamates : completely sustainable
- The principle 'thickening without thickeners'
- Fig. 1 : Examples for natural amino acids in aqueous solutions (pH 7) : a) Glutamate, b) Glycine, c) Sarcosine
- Fig. 2 : a) Surfactants based on N-lauroyl amino acids (amino acid surfactants), R : Amino acid specific rest, R* : H for glutamates and glycinates, CH3 for sarcosinates b) Soap (laurate)
- Fig. 3 : Two amino acid surfactants: Hydrogen bonds (hashed line) can be created only in acyl glycinates
- Fig. 4 : Radical change of micellar structures: Thickening by lowering the pH
- Fig. 5 : Anionic and neutral form of an amino acid surfactant: Effective spatial arrangement within micelles. For the position of the “border” between hydrophobic and hydrophilic parts see literature
- Fig. 6 : Schematic spatial arrangement of acyl glutamates within micelles
- Fig. 7 : Thickening by lowering the pH
- Table 1 : PEG-free luxurious facial cleansing oil
- Table 2 : Very mild and creamy foaming body shampoo
- Table 3 : Shower gel for natural cosmetics |
| En ligne : |
https://drive.google.com/file/d/1lAbknzP3EERz6-Qf39MDKT2xg6j5Abgp/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33958 |
in PERSONAL CARE EUROPE > Vol. 14, N° 2 (04/2020) . - p. 92-96
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