Sustainable valorization of mango peel waste by extracting bioactive compounds for functional applications

Mango peel waste is a rich source of bioactive compounds with potential for sustainable valorization. In this study, coarse and fine mango peel powders were subjected to ethanolic and supercritical CO₂ extraction. The resulting extracts were evaluated for phenolic and flavonoid content, antioxidant activity (DPPH and FRAP), as well as antibacterial, antiadhesion, and antibiofilm properties against six multidrug-resistant foodborne pathogens. The ethanolic extract from fine mango peel powder (EMPF) exhibited the highest phenolic (2488 µg GA eq/mL) and flavonoid (1282 µg rutin eq/mL) content, with quercetin (63.75 mg/L) and p-hydroxybenzoic acid (28.68 mg/L) as major compounds, and showed strong antioxidant activity (RSA = 40%, FRAP = 0.804). To enhance stability and bioactivity, EMPF was nanoencapsulated in calcium alginate (N-EMPF), yielding a favorable particle size (~ 233 nm), zeta potential (+ 23.6 mV), and encapsulation efficiency (56%). Nanoencapsulation improved antioxidant activity (RSA = 49%, TFC = 1566 µg rutin eq/mL) and significantly enhanced antimicrobial, antiadhesion, and antibiofilm effects, while maintaining low cytotoxicity in human oral epithelial cells (IC₅₀ > 100 µg/mL; viability > 70%). These findings demonstrate that nanoencapsulated ethanolic mango peel extracts represent safe, multifunctional, and sustainable sources of antioxidant, antibacterial, and antibiofilm agents with promising potential for biotechnological applications.