Fractionating of Lemongrass (Cymbopogon citratus) Essential Oil by Vacuum Fractional Distillation

Viet-Duc Phung,Dinh Phuc Nguyen,Bui Quang Minh,Dinh Nhat Do,Tuan Minh Le,Xuan Cuong Luu,Van Manh Do,Xuan-Tien Le

doi:10.3390/pr9040593

Abstract

Lemongrass essential oil has many compounds appropriate for application in foods, cosmetics, and pharmaceutical products. Of these, citral is a high-value compound of interest to industry. This work aims to evaluate the use of vacuum fractional distillation to separate lemongrass essential oil compounds, producing essential oil fractions containing high citral content. The effect of process parameters, namely vacuum pressure, type column, and energy input, on the fractionation time, content, and recovery of citral in the fractions, was investigated. The fractionation of lemongrass oils successfully provided five fractions, i.e., fraction 1 (F1), fraction 2 (F2), fraction 3 (F3), fraction 4 (F4), and fraction 5 (F5). GC-MS (Gas Chromatography-Mass Spectrometry) spectra showed that the main compound contained in F1 and F2 fractions was β-myrcene (>70%). Meanwhile, F4 and F5 were the two main fractions for citral recovery. The optimal conditions of the fractional distillation system included a column height of 400 mm, power input of 165 W, and pressure of 15 mmHg. These conditions correspond to the highest total citral content of 95%, with a recovery of 80% at the F4 and F5 fractions. Therefore, fractional vacuum distillation may be an effective method to upgrade lemongrass essential oil.

Highlights

Lemongrass (Cymbopogon citratus), belonging to the Poaceae family, is a member of an important genus with about 120 species that crop up in tropical and subtropical areas around the world
This work aims to assess the effects of vacuum pressure, type column, and energy input on the chemical profile of the obtained fractions during operation to produce essential oil fractions containing high citral content
The results of analyzing the chemical composition of lemongrass lemon essential oil by GC-MS are presented in Table 1. α-Citral (44.97%), β-citral (33.06%), and β-myrcene (7.68%)

Summary

Introduction

Lemongrass (Cymbopogon citratus), belonging to the Poaceae family, is a member of an important genus with about 120 species that crop up in tropical and subtropical areas around the world. It is widely planted over 16,000 ha throughout the world, which generates around 1000 t of essential oil per year [1]. The major active components present in lemongrass essential oil are limonene, βmyrcene, citral, geraniol, citronellol, geranyl acetate, and neral nerol [13]. Β-myrcene and limonene are aromatic composites, the main biologically active component of lemongrass essential oil is citral, a mixture of the isomeric acyclic monoterpene aldehydes neral (cis-citral) and geranial (trans-citral). Lemongrass’s essential oil comprises small quantities of geraniol, geranyl acetate, and monoterpene olefins [14,15]

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