Supercritical extraction of carotenoids from Rosa canina L. hips and their formulation with beta- cyclodextrin

the purpose of this research was to preliminary assess the suitability of a new method for the preparation of a solid formulation in form of powder composed by β-cyclodextrin and the supercritical extract of Rosa canina hips. The method implies the extraction of carotenoids, in particular β-carotene, from freeze dried fruits of R. canina with supercritical CO 2 at 70 deg;C and 300 bar, in the presence of varying quantity of ethanol as entrainer. The obtained supercritical solution is then expanded at ambient conditions into an aqueous solution of β-cyclodextrin to favour the interaction between β-cyclodextrin and the lipophilic components of the extract. β-carotene solubility (mole fraction) in supercritical CO 2 or in supercritical CO 2/ethanol mixtures were in the order of 1 10 -7. The β-carotene extracted from R. canina fruits (nearly 10 νg/g of dry matrix), interacts almost quantitatively with β-cyclodextrin affording a solid phase, which presents a low apparent solubility in water. Finally the interaction with β-cyclodextrin results in a higher concentration of the β-carotene trans-form relative to the cis-form in the extracted product when collected in an aqueous solution of β-cyclodextrin with respect to the extract in n-hexane