Sustainable solvent-free microwave extraction of giant ginger essential oil: Process intensification, kinetic modeling, and functional application for off-flavor deodorization

Natural plant-derived essential oils are increasingly explored as sustainable functional ingredients in food systems, particularly for flavor enhancement and off-flavor mitigation. This study investigates solvent-free microwave extraction (SFME) to obtain essential oil from Zingiber officinale var. officinarum (giant ginger), a high-biomass variety rich in terpenoids with potential relevance in food processing. SFME applies volumetric microwave heating to accelerate extraction without the use of organic solvents, consistent with green extraction principles. Response surface methodology was employed to optimize microwave power, sample mass, and extraction time to maximize oil yield while improving energy efficiency. Under the optimized conditions (450 W, 100 g, and 180 min), SFME produced an essential oil yield of 2.1 % (dry basis) and reduced energy consumption by approximately 35 % compared with conventional hydrodistillation. Extraction kinetics were analyzed using pseudo-first-order, Power Law, Hyperbolic, and Weibull models. The Power Law model provided the best fit at moderate microwave power (R² = 0.992), whereas the Weibull model better represented the system at higher power (R² = 0.996), suggesting a change in the dominant extraction mechanism with increasing energy input. The obtained essential oil met the physicochemical specifications of SNI 06–1312–1998, including a density of 0.878 g mL⁻¹, ethanol solubility of 1:3, and moisture content of 0.25 %, indicating its suitability for food-related applications. Sensory evaluation further showed a reduction in fishy off-flavors in treated samples, supporting its potential use as a natural deodorizing agent. SFME thus enables rapid, solvent-free extraction with improved energy efficiency while preserving essential oil quality, providing a viable approach for integrating ginger-derived flavor modifiers into sustainable food processing systems.