The citrus industry is one of the most important economic areas within the global agricultural sector. Persian lime is commonly used to produce lime juice and essential oil, which are usually obtained by batch distillation. The aim of this work was to validate a patented continuous steam distillation process and to both physically and chemically characterize the volatile fractions of essential Persian lime oil. Prior to distillation, lime juice was obtained by pressing the lime fruit. Afterwards, the juice was subjected to a continuous steam distillation process by varying the ratio of distillate flow to feed flow (0.2, 0.4, and 0.6). The distillate oil fractions were characterized by measuring their density, optical rotation, and refractive index. Gas chromatography GC-FID was used to analyze the chemical compositions of the oil fractions. The process of continuous steam distillation presented high oil recovery efficiencies (up to 90%) and lower steam consumption compared to traditional batch process distillation since steam consumption ranged from 32 to 60% for different steam levels. Moreover, a reduction in process time was observed (from 8 to 4 h). The oil fractions obtained via continuous steam distillation differed significantly in their composition from the parent compounds and the fractions.
Keywords: continuous processes; distillation by steam; essential oils.