Supercritical CO2 extraction of V. vinifera leaves: influence of cosolvents and particle size on removal kinetics and selectivity to target compounds

Leaves from Vitis vinifera L. contain potential bioactive compounds, namely: long chain aliphatic alcohols (e.g., 1-hexacosanol, 1-octacosanol and 1-triacontanol), α-tocopherol, β-sitosterol, and the triterpenes β-amyrin and lupeol. Supercritical fluid extraction (SFE) runs were measured at lab scale using: crushed and ground biomass; pure CO2 at 300 bar and 40−80 °C; and CO2 modified with 5 and 10 wt.% of ethanol or ethyl acetate. Total SFE yields ranged from 1.86 to 7.52 wt.%. The broken plus intact cells model (BICM), provided a good fitting of the SFE curves with 4.06 % error for total yield and 1.98–5.49 % for the individual yields of the said compounds. The BICM results revealed that the SFE is limited by intraparticle diffusion. Remarkable experimental and calculated selectivities were obtained for triterpenes (lupeol and β-amyrin), starting with a score of 1.7 and increasing along time to 10−100.publishe