Green-solvent extraction of guabijú (Myrcianthes pungens) fruit: a sustainable antioxidant source for oil-in- water emulsions

This study investigated the antioxidant activity of guabijú ( Myrcianthes pungens ) peel extracts and their encapsulated forms in oil-in-water emulsions. Ultrasound-assisted extraction with 50% ethanol produced phenolic-rich peel extracts that exhibited superior bioactivity compared to the pulp, including high catechin (797.28 mg·100 g⁻¹) and cyanidin-3-glucoside (163.75 mg·100 g⁻¹) contents quantified by HPLC-DAD. The peel extract was encapsulated with maltodextrin and gum Arabic by freeze-drying, achieving 87.39% encapsulation efficiency, with significant reductions in moisture, water activity, and hygroscopicity. FTIR analysis confirmed the preservation of phenolic structures. The encapsulated extract was then incorporated into oil-in-water emulsions. At concentrations ≥ 0.08%, it exhibited antioxidant performance comparable to synthetic BHT, effectively inhibiting both primary (peroxide value) and secondary (TBARs) lipid oxidation during 60 days of storage. Optical microscopy revealed improved droplet stability and delayed coalescence and Ostwald ripening in emulsions containing the encapsulated extracts. These results demonstrate the potential of guabijú peel as a natural source of phenolic antioxidants and show that freeze-drying microencapsulation effectively preserves their activity, enabling their incorporation as natural substitutes for synthetic antioxidants in emulsified systems.