Applications for supercritical fluid technology in food processing

Olive tree leaves, a residue obtained during the harvest of olives for oil production were treated with supercritical carbon dioxide to analyze the possibility of obtaining tocopherol concentrates. Oil and tocopherol extraction rates were determined as a function of pressure (25–45 MPa), particle size (0.25–1.5 mm), solvent flow (0.5–1.5 SL/min) and temperature (313–333 K). Two optimal extraction conditions were determined, considering the maximum recovery or concentration criterion. Those conditions led to a highly valuable extract of 74.5 and 97.1% (w/w) tocopherol concentration, respectively. Results obtained were compared to hexane soxhlet extraction.

Supercritical fluid extraction of tocopherol concentrates from olive tree leaves

Isolation of minor lipid components from complex lipid mixtures is receiving increased attention due to their biological activity and health benefits. Therefore, properties, health benefits and processing aspects of minor bioactive lipid components were reviewed. Literature solubility data of binary mixtures of minor lipid components (β-carotene, α-tocopherol, stigmasterol and squalene) and supercritical carbon dioxide (SCCO2) were correlated using Chrastil’s equation to determine the general trends of solubility behavior as affected by operating conditions and solute properties. Model parameters were estimated for the whole temperature range (a, b, k) and at each temperature (b′, k′). The slopes of solubility isotherms (k′) were in the range of 4.9–10.6 for β-carotene, 4.5–9.6 for α-tocopherol, 4.9–8.0 for stigmasterol and 7.3–7.6 for squalene. Estimated model parameters were used to compare solubility behavior of these solutes with components of olein glyceride series (oleic acid and triolein) as representatives of major lipid classes found in fats and oils. The findings provide the basis for the study of multicomponent lipid mixtures. Differences in the solubility behavior of components and the effect of operating conditions on solubility can be exploited for fractionation of these multicomponent mixtures to isolate the bioactive minor lipid components.

Correlating the solubility behavior of minor lipid components in supercritical carbon dioxide

Practical use of natural antioxidants in meat products in the U.S.: A review.

Natural vitamin E was extracted by supercritical fluid extraction of carbon dioxide (SFE-CO 2 ) from wheat germ. Several SFE-CO 2 parameters, such as extracting pressure, extracting temperature, and flow rate of carbon dioxide were examined as the independent variables of central composite rotate design (CCRD). Through the response surface methodology (RSM), the optimal processing conditions were determined and the quadratic response surfaces were drawn from the mathematical models. The results demonstrated that the extracting pressure, temperature, pressure × temperature interaction, and flow rate of CO 2 significantly affected the yield of the natural Vitamin E's extraction, while two interactions containing the flow rate of CO 2 had no significant effect on the yield of natural vitamin E. The optimai processing conditions of the extraction of natural vitamin E in wheat germ by SFE-CO 2 were extracting pressure 5000 PSI, extracting temperature 316 K, and flow rate of carbon dioxide 1.7 ml/min. Optimum value predicted by RSM for the concentration of natural vitamin E was 2307 mg/100g. Close agreement between experimental and predicted values was obtained. La vitamine E est extraite du germe de ble par extraction au CO 2 supercritique. L'influence des differents parametres de l'extraction (pression, temperature, vitesse du CO 2 ) est etudiee. Les conditions optimales sont determinees par la methodologie de la surface de reponse.Dans ces conditions, le rendement d'extraction de la vitamine E peut atteindre 2307mg/100g.

Huen Lee

Papers

Concentration of Tocopherols from Soybean Sludge by Supercritical Carbon Dioxide