Biological Activities of Citrus limon L. and Citrus sinensis L. Peel Essential Oils

In this study, the composition of essential oils (EOs) obtained from Citrus limon L. and Citrus sinensis L. peels and their biological activities on foodborne pathogenic bacteria and food-borne saprophytic yeasts and molds were investigated. In the lemon peel EO, 16 components were identified, mainly limonene (68.65 %) and gamma-terpinene (10.81 %). Similarly, 8 components were determined in the orange peel EO, mainly limonene (95.51 %) and beta-myrcene (1.98 %). The lemon and orange peel EOs showed a higher antibacterial effect on gram-positive bacteria used in the study compared to gram-negative bacteria. The highest antibacterial activity was detected on Staphylococcus aureus with 22.55 and 26.23 mm, respectively (P <0.05) The highest anti-fungal effects were determined at lemon peel EO, on Candida tropicalis (23.61 mm) and Rhizopus nigricans (14.15 mm) and orange peel EO, on Debaromyces hanseni spp hanseni (30.68 mm) and R. nigricans (17.23 mm) (P<0.05). The lowest minimum inhibitory concentration values were determined on S. aureus (0.023 mg/L, 0.006 mg/L), C. tropicalis (0.017 mg/L, 0.011 mg/L) and Aspergillus flavus (0.058 mg/L, 0.017 mg/mL) (P<0.05). The minimum bactericidal and fungicidal concentration values of lemon and orange peel EOs were determined on S. aureus (0.011 mg/L, 0.004 mg/L), C. tropicalis (0.011 mg/L, 0.003 mg/L) and Aspergillus flavus (0.023 mg/L, 0.015 mg/mL) (P<0.05).

Automated summary

The study investigated the composition of essential oils extracted from lemon and orange peels, as well as their biological activities on foodborne pathogenic bacteria and saprophytic yeasts and molds. The lemon and orange peel essential oils exhibited higher antibacterial effects on gram-positive bacteria, with lemon peel oil showing greater antifungal effects.