Extraction of citronella oil using two types of solvent-free microwave extraction methods: A parametric study and kinetic model

Citronella oil is a promising export commodity in Indonesia due to its high demand and stable pricing. Traditionally, the oil is extracted through steam distillation, but new methods utilizing microwave-assisted extraction (MAE) have been developed for improved efficiency. In this study, the aim was to conduct a parametric study and determine the kinetic model of essential oil extraction from citronella leaves using two types of Solvent-free microwave extraction (SFME-1 and SFME-2). Operating parameters were microwave power (300 - 600 Watt), extraction time (15 - 90 minutes), and feed ratio to distiller volume (F/D). Results indicated that the yield of citronella oil increased with longer extraction time using SFME methods, while the effect of F/D ratio on yield was minimal. Furthermore, increasing microwave power led to higher yields until reaching a maximum at 450 W, beyond which raw material damage occurred. The highest yield achieved using the SFME method was 1.591%. Physical and chemical analysis of the citronella essential oil obtained by the SFME method showed similar results to those obtained using the traditional method, but with a significantly shorter extraction time.