Davorin Bauman

Comparison of antioxidative and synergistic effects of rosemary extract with α-tocopherol, ascorbyl palmitate and citric acid in sunflower oil

The antioxidative activities of four natural antioxidants: rosemary extract (ROS.CON), α-tocopherol (TOC), ascorbyl palmitate (AP) and citric acid (CA) were studied in sunflower oil stored at 60° C. Among them, rosemary extract (ROS.CON) exhibited the best antioxidative activity, as determined by peroxide and anisidine value measurements. α-Tocopherol showed a prooxidative effect on stability of sunflower oil at tested conditions. The synergistic effects of α-tocopherol (TOC), ascorbyl palmitate (AP) and citric acid (CA) on rosemary extract (ROS.CON) were investigated. When combined with citric acid and especially ascorbyl palmitate, the rosemary extract showed an additive antioxidative effect, while by mixture with α-tocopherol a negative synergism was observed.

HIGH PRESSURE EXTRACTION OF VITAMIN E-RICH OIL FROM SILYBUM MARIANUM

Abstract The efficiency of high pressure extraction in the production of oil with a high concentration of vitamin E, from seeds of Silybum marianum , was investigated. The solvents used in extraction were liquid or supercritical carbon dioxide and liquid propane. Operating parameters were 100, 200, 300 bar and 25, 40, 60 and 80°C for CO 2 and 60, 150, 200 bar and 40, 60 and 80°C for propane, respectively. The influence of process parameters on the total yield of extraction, vitamin E composition and acid value of the extracts was investigated. Results were compared with those obtained for conventional extraction with organic solvents (n-hexane, petroleum ether, dichloromethane, chloroform). The mathematical model based on the adsorption–desorption equilibrium of oil from solid tissue, the diffusion of oil to the surface and mass transfer through external film into the bulk, described the experimental extraction results well.

Solubility of some solid triazine herbicides in supercritical carbon dioxide

Abstract Supercritical fluids can be applied for decontamination of soils and other solid materials containing residual pesticides. The solubility of solid s-triazine derivatives: ametryne, prometryne, atrazine and simazine in supercritical CO2 were measured by a static–analytic method in the pressure range from 100 to 300 bar at temperatures of 40, 60 and 80°C. The solubilities of atrazine and simazine are lower (for atrazine from 0.5×10−5 to 31.5×10−5 and for simazine from 1.7×10−5 to 19.4×10−5 mole fraction at pressures between 100 and 290 bar), than solubilities of ametryn and prometryn (for ametryn from 0.46×10−5 to 133.04×10−5 and for prometryn from 3.06×10−5 to 101.91×10−5 mole fraction for the same pressure range) because of their greater polarity. The specific functional group in s-triazines change the polarity of the compound. Atrazine and simazine have different solubilities, which also reflects the dissimilarities in their chemical structure. An analogous fact is observed for the second group of compounds (ametryn and prometryn). The solubilities depends on the solvent density and therefore the experimental binary solid–fluid equilibrium data were correlated as a function of solvent density by two different models.