Supercritical fluid extraction of bioactive compounds from sunflower leaves: comparison of analytical and pilot-scale extraction

Supercritical fluid extraction (SFE) from natural products has been widely studied as an alternative to the use of traditional techniques in the production of bioactive compounds. It has been demonstrated that this process is particularly useful when treating thermolabile compounds and solvent pollution has to be avoided. SFE can be applied to systems of different scales, from analytical scale, to pilot plant scale and up to large industrial scale. In most of these studies carbon dioxide was used as the solvent because of its relatively low critical temperature (31.1 oC), non-toxicity, non-flammability, good solvent power, ease of removal from the product and low cost. However, quantitative extraction of polar analytes requires the addition of modifier, water is would be a good cosolvent in natural products. The work described here involved the extraction of bioactive compounds from the sunflower (Helianthus annuus L) with CO2 and CO2+H2O. The extractions were carried out in an analytical Isco extractor with one extractor with a maximum capacity of 10 ml and in a pilot plant from Thar Technology provided with an extraction vessel with a capacity of 2 L. The experimental data obtained of both were compared and the implications of this analysis on the development of scale-up procedures were also discussed.