High pressure biorefinery of essential oil yielding plants into valuable ingredients
Essential oils from botanicals are usually isolated by steam or water distillation. Such process, depending on plant material, yields on average 0.5-3% of volatile oil, while the rest of the material in most cases is regarded as a waste. The effectiveness of the processing of essential oil bearing plants may be increased by a more rational utilisation of raw materials, e.g., by applying biorefining concept. Both, conventional and novel techniques as well as their combinations may be applied for this purpose. This study presents an example of fractionation of elderflowers (Sambucus nigra) into several products by using hydrodistillation and high pressure extraction techniques. Volatiles compounds were hydrodistilled, while lipophilic fraction containing essential oil constituents was isolated by supercritical fluid extraction with carbon dioxide (SFE-CO2). So far as SFE-CO2 yield depends on several process parameters, such as pressure, temperature, solvent flow rate, and process time, they were optimised using central composite design (CCD) and response surface methodology (RSM). The highest extract yield at optimal parameters was 3.63±0.07%, while hydrodistillation resulted in less than 0.05% of volatile oil. Pressurised liquid extraction (PLE) with ethanol was further applied to the residue of SFE-CO2, while the residue of hydrodistillation was divided into liquid (water soluble) and solid fractions. The former was freeze-dried giving water extract, while the latter was re-extracted by PLE with acetone. The yields of ethanol, water and acetone fractions were 25.59±0.67, 28.76±0.71, and 11.37±0.41%, respectively. Total content of phenolics, flavonoids, and radical scavenging capacity of the obtained fractions was evaluated; the composition of hydrodistilled oil and extracts were examined by chromatography and mass spectrometry.
Venskutonis, P.R. and Jonusaite, K. (2016). High pressure biorefinery of essential oil yielding plants into valuable ingredients. Acta Hortic. 1125, 399-406
elderflower, Sambucus nigra, supercritical fluid extraction, pressurised liquid extraction, total phenolic content, radical scavenging capacity