Libero Sesti Osseo

Supercritical CO2 extraction of basil oil: Characterization of products and process modeling

Abstract Supercritical CO 2 extraction of essential oil from basil leaves was performed using a semicontinuous extraction procedure and a two-stage separation technique. Both a laboratory unit and a pilot plant were used, equipped with extraction vessels of 0.4- and 20-dm 3 volume, respectively. The products were collected and analyzed by GC-MS. Waxes were found in the first separator and basil essential oil in the second separator. The yield of the extraction process was measured for three different particle sizes. A model based on the description of the mass transfer from a single spherical particle of leaf was applied. The model predictions were considered to be in fair agreement with experimental data over the entire range of experimental conditions explored.

Micronization of Lysozyme by Supercritical Assisted Atomization

Supercritical Assisted Atomization (SAA) has been used to produce lysozyme microparticles. Lysozyme has been micronized using water, buffered water at pH 6.2 and water–ethanol mixtures at different volume percentages. Precipitated lysozyme particles were spherical, with a narrow particle size distribution (PSD) ranging from 0.1 to 4 µm. The concentration of lysozyme in the liquid solvent mixture had a nonlinear effect on the particle distribution, with an increase of the X0.9 from about 1 to 3 µm varying the enzyme concentration from 5 to 20 mg/mL. Precipitation temperature was set as low as possible to avoid enzyme degradation. High‐performance liquid chromatography analysis showed no degradation of lysozyme and the enzyme activity, measured by turbidimetric enzymatic assay, only slightly decreased after SAA processing. Depending on the process conditions lysozyme retained from 95% to 100% of the biological activity compared to the untreated enzyme. Biotechnol. Bioeng. 2009; 104: 1162–1170.

Electro-spraying of a highly conductive and viscous liquid

Abstract The present work focuses on the electrohydrodynamic spraying of a viscous and highly conductive polyvinyl alcohol aqueous solution. The influence of the electric field strength on the main drop diameter, the satellite diameter and their size distribution in dripping and in jet modes has been investigated. The processes of formation of the main droplet and of the satellite have also been studied. The effect of the operating voltage on the jet formation is discussed and the existence of a hysteresis is reported.