Utilization of the integrated process of supercritical extraction and impregnation for incorporation of Helichrysum italicum extract into corn starch xerogel

Abstract

Supercritical CO2 extraction of Helichrysum italicum and impregnation of starch xerogels with the extract by using an integrated scCO2 extraction and impregnation process were performed at 350 bar and 40°C in order to produce biomaterials for possible oral intake of the extract. Xerogels produced by air-drying of acetogels and alcogels were used as carriers in the supercritical impregnation process. The effect of ethanol as a co-solvent, contact time, plant material/carrier mass ratio and xerogel preparation on the impregnation loading was studied. The highest impregnation loading (1.26±0.22%) was achieved after 5 h impregnation of the xerogel obtained from alcogel using pure scCO2 and plant material/ /carrier mass ratio of 10. Chemical analysis of the extracts showed that the addition of ethanol as co-solvent had a positive effect on scCO2 selectivity to terpene fraction and total flavonoids, while it lowered the total phenolic content. Despite the difference in chemical composition, both extracts expressed similar antioxidant activity according to the DPPH and FRAP methods. The integrated process was shown to be a feasible method for isolation and incorporation of bioactive components of H. italicum into starch xerogels.

Keywords

• antioxidant activity
• Helichrysum italicum
• supercritical extraction
• supercritical impregnation
• starch xerogels