Liquid CO2 extraction of flowers and fractionation of floral concrete of Michelia champaca Linn

Abstract

Extraction of the fresh flowers of Michelia champaca L. with liquid CO2 provided a floral extract in 1.0±0.04wt% yields. The extract so obtained contains far less waxes and is organoleptically very superior. Similarly extraction with pentane gave the so-called ‘Concrete’ in 1.58±0.06wt%. While the concrete contains co-extracted floral waxes that make it unsuitable for blending with other perfumes, direct extraction with CO2 is an expensive process mainly due to low bulk density of flowers and their availability during short flowering season. On the other hand, fractionation of the concrete with liquid CO2 to separate the waxy components has provided solvent and almost wax free fractions. The duration of extractive fractionation has been optimized for selective extraction with liquid CO2 at 62bar. These liquid CO2 fractions of concrete and liquid CO2 extract of flowers were analyzed by GC and GC/MS and their composition compared with that of concrete and partially de-waxed absolute obtained in the conventional way. The major fragrance compounds enriched in the direct liquid CO2 extract were methyl benzoate (11.5±0.8%), phenyl ethyl alcohol (5.0±0.6%), phenyl acetonitrile (10.4±1.1%), indole (1.2±0.3%), methyl anthranilate (1.3±0.5%), E-β-ionone (1.5±0.4%), and Z-methyl jasmonoate (1.0±0.3%). The liquid CO2 fractionation of concrete is a practical process and the first fraction is comparable with direct liquid CO2 flower extract in terms of composition of the major compounds.