Composition Analysis and Biological Activity of Ginger Essential Oil Extracted by Different Methods

To evaluate the impacts of different extraction methods on the properties of ginger essential oil, this study investigated the yield, physicochemical properties, thermodynamic characteristics, and functional group composition of ginger essential oil extracted by four techniques: steam distillation (SD), ultrasound-assisted steam distillation, enzymatic hydrolysis combined with steam distillation and ultrasound-enzyme synergistic assisted steam distillation (UEASD). In addition, the chemical composition, antioxidant and antibacterial activity of the extracted oils were evaluated. The results indicated that UEASD significantly increased the yield of ginger essential oil compared with the other methods (P < 0.05) and improved the physicochemical and thermodynamic properties. Fourier transform infrared spectroscopy (FTIR) analysis revealed that ginger essential oil mainly contained terpenes, alcohols, ketones and aldehydes. Gas chromatography-ion mobility spectrometry (GC-IMS) identified 85 compounds, with the essential oil extracted by UEASD being rich in terpenes (48.16%), ketones (13.16%), and aldehydes (2.63%). Moreover, the UEASD-extracted oil exhibited strong scavenging capacity against 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and hydroxyl radical, with half maximal inhibitory concentration (IC₅₀) of 1.84, 1.20, and 2.26 mg/mL, respectively, which was higher than that of the positive control VE. The essential oil was effective against Staphylococcus aureus, Escherichia coli, and Penicillium citrinum. This study provides a scientific basis and technical support for the development of high-quality, value-added ginger essential oil products.