From phenolics to phenolipids: Optimizing antioxidants in lipid dispersions

Natural non-polymeric phenolics are known to be powerful antioxidants, but their use for preventing lipid oxidation in unsaturated fatbased products, such as foodstuffs and cosmetics, is limited owing to their hydrophilic character. A promising technique - referred to as lipophilization - consists of covalently grafting a lipid moiety to the phenolic part to improve both surface activity and oil solubility of a given phenolic antioxidant. After being based on empiricism for decades, the lipophilization of phenolics is today more rationalized, as recent advances in the field have shown that the grafting of a medium chain-length is the best strategy to design powerful, custom-made phenolic antioxidants to protect lipid dispersion against oxidation. To illustrate, we report here the main strategies in the lipophilization of phenolic acids, the effect of such modification on the antioxidant properties, and current and potential applications of the resulting phenolipids.