Propolis: A Natural Bioactive Compound with Emerging Roles in Functional Food Applications

Propolis, a resinous substance biosynthesized by honeybees from plant exudates and beeswax, has been valued for centuries in traditional medicine and is now increasingly recognized as a promising natural bioactive compound for functional food applications. Its complex phytochemical profile, mainly comprising flavonoids, phenolic acids, and terpenoids, confers potent antioxidant, antimicrobial, and anti-inflammatory properties that position it as a compelling candidate for use as a natural food preservative and bioactive additive. Despite this considerable potential, the widespread incorporation of propolis into food systems remains largely constrained by two main physicochemical limitations: its intense characteristic aroma, attributable to volatile terpenes and phenolic esters, which adversely affects sensory acceptance, and its inherent hydrophobicity, which prevents uniform dispersion in aqueous food matrices. This review critically examines three major technological strategies developed to overcome these barriers: (i) microencapsulation employing biopolymer wall materials, including alginate, chitosan, whey protein, and arabic gum, to mask organoleptic properties and enable controlled release; (ii) nanoemulsification to enhance water dispersibility and improve oral bioavailability; and (iii) the formulation of water-soluble propolis extracts through polyethylene glycol-based solvents or cyclodextrin complexation. In addition, this review provides a comprehensive assessment of the global chemical diversity of propolis and its bioactive properties as they relate to food preservation efficacy. Notwithstanding recent technological advances, critical research gaps persist regarding optimal effective concentrations, validated delivery systems, and scalable formulation strategies necessary for commercial food-grade applications. Addressing these gaps is essential for propolis to fulfill its considerable potential as a safe, widely accepted, and commercially viable natural food additive in next-generation functional food systems.