Optimized essential oil extraction method based on salt solution-enhanced homogenization pretreatment and microwave extraction for Kaempferia galanga L

The primary purpose of this study is to develop a highly efficient extraction method to meet the growing demand for Kaempferia galanga essential oil (KGEO) in various industries. In this study, an innovative approach for extracting essential oil from fresh K. galanga rhizomes using salt solution-enhanced homogenization pretreatment and microwave extraction (HP-SOME) was proposed. A kinetic study was conducted on the extraction process of essential oil. The key factors were screened using the Plackett–Burman Design and optimized using the Box-Behnken Design. Under the optimization parameters: sodium chloride concentration of 1.5 %, microwave power of 475 W, and microwave time of 23 min, the actual yield was 5.26 ± 0.10 %. The HP-SOME method exhibited a significant increase of 58.91 % in essential oil yield compared to that of the hydrodistillation method (3.31 ± 0.10 %). In addition, the composition of the KGEO was determined using Fourier transform infrared spectroscopy, Raman spectroscopy, and gas chromatography-mass spectrometry. The KGEO obtained by HP-SOME had a 6.26 % increase in the main component ethyl p-methoxycinnamate and a 4.13 % increase in ethyl cinnamate compared to that obtained by the HD method. Investigations into antimicrobial activity revealed that KGEO extracted by the HP-SOME method exhibited superior and more comprehensive antimicrobial characteristics. In conclusion, the HP-SOME method demonstrated remarkable capabilities in obtaining KGEO with notable efficiency, yield, and quality. This method holds great promise in the field of essential oil extraction.