Antioxidant Potential of Artichoke and Broccoli Leaf Extracts in Oil-in-Water Emulsions Through Different Delivery Systems: Direct Addition, Alginate Films, and Alginate Beads

Abstract

This study evaluates the antioxidant effectiveness of broccoli and artichoke leaf extracts delivered through different strategies(direct addition, alginate films, and alginate beads) in oil-in-water emulsions as natural antioxidants to prevent lipid oxidation.Leaf extract total polyphenol content (TPC) was determined, with artichoke leaf extract showing higher values (0.89 mgGAE/mL) than broccoli leaf extract (0.47 mg GAE/mL). The extracts were characterized by UHPLC-ESI–MS/MS; broccolileaf extracts were mainly characterized by glucosinolates (glucoiberin and glucoraphanin) together with kaempferol andquercetin derivatives, whereas artichoke extracts were richer in less glycosylated phenolics, including luteolin, apigenin,and hydroxycinnamic acids. Films and beads were analyzed for mechanical properties, morphology, and polyphenol releasekinetics. Beads showed a higher release of the TPC (54.7–78.6%) compared with films (22.6–44% released). Lipid oxidationand semiquantitative distribution of TPC between emulsion phases were also determined. Results showed that artichokesystems exhibited higher antioxidant activity, with lower primary (38.79 meq hydroperoxide/kg emulsion for artichokeleaf extracts at 10%, AL10%) and, also, secondary lipid oxidation. Alginate films and beads incorporating extracts showedsimilar effectiveness to 10% leaf extracts directly added. The highest partition coefficient (ratio of polyphenol in oil phaseand in water phase) was found in emulsions with artichoke leaf extracts (3.7 for AL3.3%) due to its lower polarity nature and,therefore, favoring localization in oil phase and enhancing oxidative protection. Our findings highlight the strong potentialof broccoli and artichoke leaf extracts and alginate systems as natural antioxidants for preventing the lipid oxidation inemulsified food systems.