Extraction of mace (Myristica fragrans Houtt.) essential oil by microwave air-hydrodistillation: Mechanistic kinetics and chemical evaluation

This study investigates Microwave Air-Hydrodistillation (MAHD) as an alternative to conventional hydrodistillation for extracting essential oil from Myristica fragrans Houtt. mace. Process variables including microwave power (300–600 W), feed-to-solvent ratio (0.20–0.30 g/mL), and particle size (20–100 mesh) were evaluated to optimize yield while reducing energy and solvent usage. Under optimal conditions (600 W, 0.30 g/mL, 60 mesh, 120 min), MAHD achieved a yield of 10.71%, with faster extraction and lower specific energy demand compared to conventional methods, while meeting SNI 06-2388-2006 and ISO 3215:1998 standards. Kinetic analysis using five models showed a transition in extraction behavior: the Weibull model best described low–medium power conditions, whereas the Power Law model dominated at high power (R² up to 0.9989), indicating a shift from diffusion-controlled release to rapid surface-driven extraction. GC–MS results revealed that the oil was rich in aromatics (38.84%) and oxygenated monoterpenes (25.12%), with major compounds including methyl eugenol, eugenol, safrole, terpinen-4-ol, and myristicin . Compared with hydrodistillation, MAHD favored the recovery of oxygenated and phenylpropanoid compounds. FTIR confirmed the presence of characteristic functional groups. The oil exhibited strong antibacterial activity against Staphylococcus aureus and moderate inhibition of Escherichia coli , along with moderate antioxidant activity (IC₅₀ = 1.14 mg/mL). MAHD offers a viable and energy-efficient approach for producing high-quality mace essential oil.