Physicochemical and Biological Activities of Alpinia galanga (L.) Willd. Essential Oil Extracted by Pulsed Electric Field and Ultrasonication Pretreatments of Hydrodistillation

The Alpinia genus has long been used in many countries as a traditional medicine and is known for its antioxidant and antimicrobial properties. Galangal essential oils (GEO) increase the therapeutic potential of various Alpinia species. However, the extraction of high-quality GEO is challenging because of its low yield and inconsistent quality. This study investigated alternative pre-treatment methods before hydrodistillation of Alpinia galanga (L.): Pulsed electric field (PEF) with parameters 3000 V, 5000 Hz for 30 min and ultrasonication with parameters 50 W/m, A = 40%, for 30 min with the addition of distilled water 1:1 (v/m) Willd. PEF pre-treatment resulted in the highest GEO yield (0.88% ± 0.11%) and a greater proportion of 1,8-cineole (25.01%) compared to the control and ultrasonication pre-treatment. Furthermore, PEF significantly enhanced antioxidant activity, as shown by DPPH (41.88 ± 0.07 µg/mL) and ABTS (46.43 ± 0.02 µg/mL) assays. Both PEF and ultrasonication improved antimicrobial activity against Escherichia coli than Staphylococcus aureus, with PEF demonstrated the highest inhibitory activity against Aspergillus niger compared to Saccharomyces cerevisiae. These results suggest that PEF is an effective green pre-treatment method fpr enhancing both yield and bioactivity of GEO form A. galanga (L.) Willd., highlighting its potential for application in the food and pharmaceutical industries.