Unlocking green efficiency: Optimized solvent-free microwave extraction of essential oils from zingiber officinale

¹ Department of Chemical Engineering, Institut Teknologi Sepuluh Nopember (ITS)
² Department of Agricultural Technology, Brawijaya University

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

SFME has emerged as a green and efficient technique for essential oil recovery; however, its application to ginger rhizomes and the identification of kinetically operating conditions remain limited. This study investigates the time-dependent extraction behavior and extraction kinetics of ginger essential oil using SFME under varying operating conditions. Microwave power and sample mass were systematically varied to generate yield–time profiles, which were subsequently analyzed using several kinetic models, including first-order, second-order, power law, hyperbolic, Elovich, and Weibull models. The extraction process exhibited a characteristic two- stage behavior, consisting of a rapid initial extraction followed by a slower diffusion-controlled stage. Kinetic analysis revealed that empirical models, particularly the power law and Weibull models, effectively described the non-linear extraction behavior, indicating mixed mass transfer control mechanisms. At a constant microwave power of 450 W, sample mass significantly influenced extraction kinetics, with intermediate solid loading providing a balanced extraction rate and favorable characteristic extraction time. Based on kinetic efficiency and extraction stability rather than final yield alone, the optimal operating condition was identified at 450 W with a sample mass of 200 g. This kinetic-based evaluation provides mechanistic insight into SFME of ginger and offers a rational efficient operating conditions for green extraction.