Roselle (Hibiscus sabdariffa L.) phenolic profile and lipid oxidation inhibition in a cocoa butter model system: Impact of extraction method

The demand for natural antioxidants has stimulated interest in plant-based alternatives to synthetic preservatives for lipid-rich foods. Roselle (Hibiscus sabdariffa L.), a source of phenolic acids, flavonoids, and anthocyanins, is widely studied for antioxidant activity; however, how extraction conditions shape phenolic fingerprints and functional efficacy in lipid systems remains insufficiently resolved. This study compared six extraction methods including hot and cold brewing, hot and cold ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and maceration (control) and evaluated physicochemical properties (pH, viscosity, color), phenolic composition (HPLC-DAD), antioxidant capacity (DPPH IC₅₀), and lipid oxidation inhibition in a cocoa butter model system. Oxidative stability was assessed under accelerated storage (20–40 °C, 15 days) using peroxide value, p -anisidine value, and TOTOX. Extraction method influenced phenolic profiles and oxidation endpoints. Cold-UAE yielded the lowest IC₅₀ (9.81 mg L⁻¹) and the lowest final p -anisidine value (2.79) and TOTOX (7.65) at 40 °C on day 15. By contrast, conventional cold brew, despite a higher HPLC-based phenolic signal, showed weaker oxidation protection, indicating that phenolic composition is a more informative determinant of functionality than phenolic abundance alone. Overall, the results link extraction-dependent phenolic fingerprints to lipid oxidation metrics, supporting cold-UAE as an approach to obtain roselle extracts with measurable efficacy in cocoa butter and other lipid-rich food systems. © 2026 The Authors.