Phospholipids are natural emulsifiers: structure / performance relationship
Résumé
The use of synthetic surfactants in the cosmetic industry is more and more criticized due to many disadvantages related to toxicological and environmental considerations. Therefore, a number of strategies are being investigated to prepare stable emulsions, including the utilization of proteins from plant origins. Among others, phospholipids are promising surfactants [1,2] but own a complex structure as visible on Figure 1. They consist of a glycerol molecule (II) with two esterified hydroxyl with fatty acids (I). The residual hydroxyl is esterified by a phosphoric acid molecule (III), this last being associated to either a nitrous group (choline, serine or ethanolamine) or a sugar (inositol) (IV). Thus, they require intensive investigations to build structure – properties relationship in any attempt to optimize their performance.
The main goal of the present project was to better understand build and accumulate the knowledge about the behavior of different phospholipids for making emulsions and stabilizing interface.
A strong axis aimed to figure out the structural properties effects by correlating the structural and physicochemical properties with emulsification performances. A key point also set-up an action plan in order to understand and compare the interface behavior of these ingredients with conventional surfactant. Finally, ones selected the best phospholipids candidates as surfactant, the texture properties of different cosmetic grade formulations could be evaluated and compared with the one obtained using conventional synthetic surfactant.
The whole results unambiguously demonstrate a powerful way for developing innovative efficient surfactants issued from natural resources.
References
[1] Li, J. et al. A Review on Phospholipids and Their Main Applications in Drug Delivery Systems. Asian J. Pharm. Sci. 10, 2015, 81–98
[2] Kjellin, M.; Johansson, I. Surfactants from Renewable Resources; John Wiley & Sons, 2010.