Ability of Surface-Active Antioxidants To Inhibit Lipid Oxidation in Oil-in-Water Emulsion

Abstract

Lipid oxidation in dispersed lipids is prevalent at the oil-water interface where lipid hydroperoxides are decomposed into free radicals by transition metals. Free radical scavenging antioxidants are believed to be most effective in lipid dispersions when they accumulate at the oil-water interface. The surface activity of antioxidants could be increased by their conjugation to hydrocarbon chains. In this study, p-hydroxyphenylacetic acid (HPA) was conjugated with either a butyl or dodecyl group. The HPA conjugates were more effective at decreasing interfacial tension than unconjugated HPA, indicating that they were able to adsorb at lipid-water interfaces. However, free HPA was a more effective antioxidant than butyl and dodecyl conjugates in Menhaden oil-in-water emulsions as determined by both lipid hydroperoxides and thiobarbituric acid reactive substances. The increased antioxidant activity of free HPA could be due to its more effective free radical scavenging activity and its higher concentration in the lipid phase of oil-in-water emulsions in the presence of surfactant micelles where it can act as a chain-breaking antioxidant.

Antioxidant effects of extra virgin olive oil enriched by myrtle phenolic extracts on iron-mediated lipid peroxidation under intestinal conditions model

“…Gallic acid was identified by comparing its retention time and spectral data with its authentic standard using HPLC-DAD signal. In Weiss, Villeneuve, López Giraldo, Figueroa-Espinoza, & Decker, 2007). In our study, the lipid peroxidation was induced by free radicals derived from AAPH decomposition which occurred in the aqueous phase.Gallic acid is a water soluble antioxidant and is predominantly located in the aqueous-interfacial regions of the phospholipid dispersion (Losada Barreiro, Bravo-Díaz, Paiva-Martins, & Romsted, 2013) where it may interact with AAPH derived radicals and consequently reduce the production of conjugated dienes.…”

“…Lipid oxidation in dispersed lipid phase is prevalent at the oil-water interface, where lipid hydro-peroxides are decomposed into free radicals by transition metals or other oxidant agents. Thus, free radical scavenging antioxidants are believed to be most effective in lipid dispersions when they accumulate at the oil-water interface (LosadaBarreiro, Bravo-Díaz, Paiva-Martins, & Romsted, 2013;Yuji, …”

Investigation of Distribution of Antioxidant Compounds from Natural Sources and Study of Lipid Protection in Oil-in-Water Emulsions

“…4,[10][11][12] However, the results of other studies are not in accordance with this theory. [13][14][15] As such, some authors have attempted to improve the polar paradox theory, [16][17][18] employing esters from phenolic acids, such as esters of the acids p-hydroxybenzoic, caffeic and vanillic. 16,19,20 However, some of these compounds (e.g., esters of p-hydroxybenzoic acid) are related to serious health problems, such as mammary tumors in humans and reproductive problems in animals, 21 limiting the future extrapolation of these results to other food sources, as well their application in industrialized foods.…”

From phenolics to phenolipids: Optimizing antioxidants in lipid dispersions

“…However, owing to their rather polar character, these molecules are not optimal in dispersed lipid systems, such as emulsions, micellar solutions or liposomes suspensions, since they tend to preferentially concentrate into the aqueous phase, far away from the oil/water interface where lipid oxidation is assumed to occur. Based on this observation, lipophilization has been early considered to improve the surface-active properties of polar antioxidants, and thus their effectiveness in such dispersed lipid systems [1]. Basically, the modification consists of grafting a lipid moiety via different reactions (etherification, esterification, transesterification and amidation) and catalytic approaches (homogeneous vs heterogeneous, chemical vs enzymatic) according to the structure and the reactivity of starting molecules [2][3][4].…”