Résumé : |
Contrary to what their name might otherwise imply, exotic butters being used in cosmetic formulations are not sourced from milk and contain no dairy by-products. By definition, exotic butters are naturally occurring, plant-derived lipids that are generally solid at room temperature, but melt readily on contact with the skin. The definition has been extended to include man-made butters produced via blending of natural (plant derived) oils with fractionated or hydrogenated oils to simulate the properties of a “butter”. Naturally occurring butters are extracted by various means and usually come from the seeds or kernels of the source plant. Expeller pressing (physical extraction) and chemical (solvent) extraction are the most commonly employed techniques to obtain the lipid butter content. The fatty acid chemistry and composition of a butter are directly responsible for its physical qualities such as melting point, hardness, stability and the reason that this oil is a solid at room temperature in the first place. Exotic butters such as shea and cocoa are considered “classic” emollients. They have been relied on as integral cosmetic oil-phase ingredients for decades. They both have fatty acid profiles that lend themselves towards penetrating the epidermis in order to hold in moisture, and to bring nutrients to the different strata of the skin. They have both shown excellent miscibility, acceptable oxidative stability (with cocoa butter outperforming shea butter in terms of shelf life), along with higher levels of saturated fatty acids contributing to emulsion stability. These classic butters, along with a slew of new emerging exotic butters can build viscosity in emulsions and add complexity and depth to anhydrous product formulations. Indeed, naturally occurring butters such as mango butter, shea butter, sal (Shorea Robusta) butter, cupuacu (COO-PA-SOO) butter, and tucuma (TOO-COO-MA) butter have proven to have aesthetically pleasing properties. Many companies such as The Body Shop and natural cosmetics giant Burt’s Bees are marketing them as pure “body butters”. With such an increase in attention given towards natural cosmetics, certified organic cosmetics and the ayurvedic personal care movement that is exploding worldwide, other lesser known butters such as sal (Shorea), kokum (CO-COME), illipe (E-Lip-A), murumuru, (MOO-ROO-MOOROO) and mowrah (MO-RA) butters will give cosmetic chemists variety when picking a CBS or SBS (cocoa butter substitute, shea butter substitute). These butters promise to offer a bevy of different aesthetic qualities with benefits to personal care products ranging from oxidative stability, humectant properties, anti-inflammatory properties to curative abilities for such maladies as eczema, psoriasis, dermatitis and sun burn. While not a cure-all by any means, the level of versatility and efficacy that these emerging natural ingredients can offer to almost any kind of formula should not be ignored or taken lightly. |