Person: Calvo Garrido, María Lourdes
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First Name
María Lourdes
Last Name
Calvo Garrido
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
Ingeniería Química
Identifiers
2 results
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Item Astaxanthin encapsulation in ethyl cellulose carriers by continuous supercritical emulsions extraction: A study on particle size, encapsulation efficiency, release profile and antioxidant activity(Journal of Supercritical Fluids, 2019) Tirado, Diego ; Palazzo, Ida; Scognamiglio, Mariarosa; Calvo Garrido, María Lourdes; Della Porta, Giovanna; Reverchon, ErnestoSupercritical emulsions extraction (SEE)technology was used to encapsulate astaxanthin (AXT)in ethyl cellulose (EC). The operating parameters were 8 MPa and 311 K with an L/G ratio of 0.1 (CO2 flow rate of 1.4 kg/h). Several emulsion formulations were tested, fixing the oil-water ratio at 20:80 (ethyl acetate/water)and varying EC concentration in the oily phase from 1.0–2.5% mass and the surfactant amount in the water phase from 0.1 to 0.6% mass. Both parameters influenced carriers morphology, size and distribution; a correlation between the EC amount in oily phase and its dynamic viscosity was proposed to explain the droplets/carriers size variation observed. Carriers aggregation was monitored at surfactant concentration higher than 0.3% mass. The best emulsion formulation was obtained using 1.0% mass of EC in the oily phase and 0.1% mass of surfactant in the water phase; in these conditions spherical nanocarriers with unwrinkled and smooth surface were obtained with a size of 242 nm and Poly Dispersity Index of 0.16. EC mass recovery was of 90%. Higher carrier mean size of 363 nm (Poly Disperity Index of 0.31)was measured when AXT was encapsulated in the same conditions, achieving an encapsulation efficiency of 84%. The carriers were loaded with 21 mg/g of AXT and showed an excellent antioxidant capacity, measured as Trolox equivalent (Trolox equivalent per kg of pure AXT), and equivalent to 3900 M Trolox. In vitro release profiles obtained in a simulated intestinal fluid (SIF)at pH 7.2 and 310 K, showed a release of 70% of the total encapsulated AXT after 10 h.Item The Selective Supercritical Extraction of High-value Fatty Acids from Tetraselmis suecica using the Hansen Solubility Theory(Chemical Engineering Transactions, 2019) Tirado, Diego ; Rousset, Amandine; Calvo Garrido, María LourdesThe aim of this work was to test the utility of the Hansen theory to predict the best cosolvent for supercritical carbon dioxide (sc-CO2) to reach the selective extraction of fatty acids from Tetraselmis suecica. The order in the cosolvent power was established with five organic solvents used in food production: acetone, diethyl ether, ethanol, n-hexane and methanol. Predictions focused on the selective extraction of oleic, linoleic and α-linolenic acid. The cosolvent power depended on the fatty acid, but in general, the best cosolvent for the three target compounds was ethanol. Predictions were validated through equilibrium data and extraction yields from T. suecica. Operating at 305.15 K and 20 MPa, the extracted oil with the sc-CO2-ethanol (5 % mass fraction) mixture significantly improved the content of the target fatty acids compared with pure sc-CO2; e.g. the α-linolenic acid content was 16 % in the oil obtained with pure sc-CO2 while it was 25 % in the oil obtained with sc-CO2 + 5 % ethanol. However, the Hansen theory predicted that the miscibility enhancement of the fatty acids caused by increasing ethanol concentrations in the supercritical solvent mixture was not progressive. In fact, at high pressures and high ethanol concentrations, it was predicted up to less than half the miscibility enhancement.