A biorefinery approach for the simultaneous obtention of essential oils, organic acids and polyphenols from citrus peels: Phytochemical characterization and bioactive potential

This investigation evaluates the valorization of citrus peels (lemon, tangerine, and orange) to recover both on-polar and polar fractions simultaneously. Citrus essential oils, abundant in limonene (74.4-33.7 %), exhibited great antioxidant activity (IC₅₀ = 2.002 mg/mL) and Campylobacter jejuni halo inhibition (2.9 cm), particularly in tangerine and orange essential oils. The aqueous extracts were rich in quinic and malic acid (10-78.8 g/100 g), along with polyphenols (22.7-5.2 mg/g), such as diosmetin, luteolin, and eriodictyol glycosides. Tangerine's aqueous fraction showed the highest inhibition of oxidative hemolysis (IC₅₀ = 102 μg/mL) and Staphylococcus aureus (MIC = 2.5 mg/mL). Whereas lemon was most effective against lipid peroxidation (IC₅₀ = 1.33 mg/mL) and gastric adenocarcinoma proliferation (IG₅₀ = 83 μg/mL). Principal component analysis correlated the in vitro bioactivities with each compound and citrus type, underscoring the potential of citrus peels as a cost-effective, sustainable source of value-added compounds with tailored commercial applications.