Bioactive Phenolics from Medemia argun: Biological Activities, Molecular Docking, Encapsulation in Alginate–Whey Protein Hydrogel Beads, and Functional Yoghurt Fortification

Abstract

Medemia argun is a rare desert palm rich in phenolic compounds with promising biological activities; however, the instability and poor compatibility of phenols in dairy systems limit their functional application. This study characterized the phenolic composition and biological activities of M. argun phenolic extract (MAPE), developed sodium alginate–whey protein concentrate (SAlg/WP) hydrogel beads for phenolic encapsulation, and evaluated their application in fortified yoghurt. HPLC identified quercetin and gallic acid as the predominant phenolic compounds. Antioxidant, antimicrobial, antiviral, and molecular docking analyses were performed, while SAlg/WP–MAPE beads were characterized by encapsulation efficiency analysis, FTIR, and scanning electron microscopy. Fortified yoghurt containing different concentrations of encapsulated MAPE was evaluated for color, syneresis, pH, and antioxidant activity during 14 days of refrigerated storage. MAPE exhibited strong antioxidant and broad-spectrum antimicrobial activities against bacterial and fungal strains, as well as promising antiviral activity against hepatitis A virus (HAV), with an IC50 of 104.89 μg/mL and a selectivity index of 1.6. Molecular docking revealed favorable interactions of rutin, chlorogenic acid, and rosmarinic acid with the HAV 3C protease. SAlg/WP beads achieved 78.92% encapsulation efficiency, while FTIR and SEM confirmed successful phenolic entrapment. Encapsulation effectively preserved MAPE functionality and significantly enhanced yoghurt antioxidant activity during storage, demonstrating its potential for functional dairy applications.