Polyphenols from Pliniajaboticaba peels: cellular antioxidant activity, anti-obesity effects, microencapsulation,...

Polyphenols from jabuticaba berry (Plinia jaboticaba) peels were recovered via ultrasound-assisted extraction, with sample-to-solvent ratio and extraction time optimised using response surface methodology. Optimal conditions were established at a sample-to-solvent ratio of 1:40 (w/v) and a reaction time of 6.75 min. The resulting freeze-dried jabuticaba peel extract (JPE) exhibited a total phenolic content of 9403 ± 364 mg/100 g, with flavonoids contributing 5196 ± 518 mg/100 g. Major phenolic constituents included ellagic acid (3766 ± 98 mg/100 g), procyanidin B2 (1828 ± 27 mg/100 g), vescalagin (555 ± 21 mg/100 g), gallic acid (307 ± 4 mg/100 g), (-)-epicatechin (243 ± 31 mg/100 g), and cyanidin-3-O-glucoside (196 ± 2 mg/100 g). JPE exhibited chemical antioxidant capacity across multiple assays, consistent with cellular antioxidant activity in H₂O₂-challenged human-derived hepatocellular carcinoma (HepG2) cells. In vitro assays also revealed anti-cholesterolemic (IC₅₀ = 40.91 μg/mL), antidiabetic (IC₅₀ = 33.52 μg/mL), and anti-obesity (IC₅₀ = 30.50 μg/mL) potential. Anthocyanins in JPE exhibited high structural reversibility (90.52 ± 0.40%) during pH cycling from pH 2 to 10. The ionotropic gelation technique effectively entrapped the phenolic fraction within an alginate-carboxymethylcellulose matrix, achieving an encapsulation efficiency of 75.23 ± 1.67%. Antioxidant release from microcapsules was greater under simulated gastric than intestinal conditions. Incorporation of JPE into a model beverage enhanced both chemical and cellular antioxidant activity, with pasteurisation preserving flavonoid and anthocyanin contents. The JPE-enriched beverage achieved an acceptability index of 71%, with no significant differences (p > 0.05) across gender or age groups. Collectively, JPE represents a promising functional ingredient for sustainable food applications aimed at mitigating oxidative stress.