Optimized recovery of essential oils from citrus peels using cellulase-salt pretreatment and microwave hydrodistillation: A study of yield and functional activities

Citrus fruit peel contains a large amount of essential oil, which has great application potential in the food and cosmetics industries. To further increase the yield of essential oil extraction, this study detailly explored the pretreatment of raw materials by combining cellulase and inorganic salts. Then, the essential oil of 3 Citrus fruits (lemon, navel orange, and pomelo) were extracted by microwave-assisted water distillation. The study optimized the essential oil yield through single-factor experiments and response surface methodology and compared the antioxidant properties and antifungal activities of the 3 essential oils. The combination of cellulase and inorganic salts significantly improved the extraction efficiency of essential oil. Moreover, the yield of lemon essential oil (27.61 mL/kg DW) was significantly higher than other samples. The gas chromatography-mass spectrometry (GC-MS) detection results confirmed that 15 compounds were the same in these raw materials. The results of the activity experiments indicated that compared with navel orange and pomelo, lemon essential oil exhibited better anti-fungal ( Colletotrichum fructicola and Colletotrichum fioriniae ) activity and antioxidant activity. Therefore, this study provides potential ideas for the deep processing of Citrus fruit by-products. • Citrus essential oil (EO) are proposed as natural antimicrobials and antioxidants. • Microwave-assisted hydrodistillation with cellulase-salt pretreatment boosts EO yield. • The method offers a green and efficient approach to extract Citrus EOs. • Lemon peel EO showed strongest antifungal and antioxidant activity in three assays.