Precipitation of [beta]-carotene and PHBV and co-precipitation from SEDS technique using supercritical CO2 (original) (raw)
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The Journal of Supercritical Fluids, 2008
The objective of this work was to investigate the application of the solution enhanced dispersion by supercritical fluids (SEDS) technique for the precipitation of pure -carotene and copolymer poly(3hydroxybutirate-co-hydroxyvalerate) (PHBV), as well as some encapsulation tests of the solute in the biopolymer. The following parameters were investigated in the precipitation of pure -carotene: pressure (8.0 and 12.0 MPa), anti-solvent flow rate (20-40 mL/min) and concentration of -carotene in an organic dichloromethane solution (4 and 8 mg/mL). For pure -carotene, the results showed that the mean particle size varied from 3.8 to 246.8 m, depending on the processing conditions. The morphology of -carotene was modified from plate-like to leaf-like particles, as verified by micrographs of scanning electronic microscopy (SEM). For the PHBV precipitation, the SEM micrographs showed that for all experimental conditions the morphology of polymer was different from the unprocessed material. The precipitated polymer presented a quasi-spherical shape with interconnected particles in the sub-micrometric range (particle size in the range of 278-570 nm), while the unprocessed material was composed of films and large blocks. The co-precipitation tests showed that the best ratio of -carotene to PHBV in solution was 1:3 (w/w), which resulted in approximately 80% of encapsulation. Fluid phase behavior of the ternary systems CO 2 + dichloromethane + -carotene and CO 2 + dichloromethane + PHBV was also investigated with the aim of elucidating the region of the phase diagram in which the precipitation occurs. Phase equilibrium data were measured in the temperature range of 303-343 K, with CO 2 compositions ranging from 40 to 90 wt% for -carotene, and from 30 to 90 wt% for PHBV. Vapor-liquid and also solid-vapor-liquid phase transitions were observed in the phase equilibrium study. It was observed that the presence of -carotene or PHBV in the ternary mixture had a little influence on the fluid phase behavior of the systems.
The Open Chemical Engineering Journal, 2010
The objective of this work was to investigate the application of supercritical carbon dioxide as antisolvent for the co-precipitation of -carotene and poly(hydroxybutirate-co-hydroxyvalerate) (PHBV) with dichloromethane as organic solvent. For this purpose, the concentrations of -carotene (1 to 8 mg.cm -3 ) and PHBV (20 to 40 mg.cm -3 ) in the organic solution were varied keeping fixed temperature at 313 K, pressure at 8 MPa, solution flow rate at 1 cm 3 .min -1 and antisolvent flow rate at 39 g.min -1 . The morphology of co-precipitated particles were spherical with very irregular and porous surface for some conditions and very smooth surfaces for others as verified by micrographs of scanning electronic microscopy (SEM). Results show that it is possible to achieve encapsulation efficiency values as high as 35 % just manipulating the concentration ratio of solute to polymer in organic solution. The methodology adopted for the quantification of -carotene encapsulated was demonstrated to be adequate.
Co-precipitation of carotenoids and bio-polymers with the supercritical anti-solvent process
The Journal of Supercritical Fluids, 2007
Carotenoids are widely used as natural colorants in food or pharmaceutical industries. In some industrial formulations, these carotenoids are mixed with bio-polymers, to improve the stability of the carotenoid, its dissolution rate in water, and to make the dosage and the handling of the product easier. The supercritical anti-solvent (SAS) process is specially suitable for the production of fine powders of these mixtures, as it yields solvent-free products with a reduced thermal degradation or oxidation of the carotenoids. In this work, the application of the SAS process to the precipitation of carotene or lutein with poly-ethylene glycol (PEG) has been studied. The influence of different process parameters, including the operating pressure and temperature, the polymer/carotenoid concentration ratio, and the CO 2 flowrate have been studied experimentally. Additionally, a phase equilibrium model of these systems based in the perturbed hard-sphere-chain equation of state (PHSC EoS) has been developed. This model is helpful for the analysis of the experimental results. In particular, this model predicts the apparition of a liquid-liquid immiscibility region at moderate temperatures due to the co-solvent effect of CO 2 on PEG. This explains the difficulties found in the precipitation experiments performed at these conditions. The existence of this phase behavior has been corroborated by performing batch gas anti-solvent (GAS) precipitation experiments in a windowed vessel.
The Journal of Supercritical Fluids, 2011
The main objective of this work was to investigate the characteristics of the in vitro release of -carotene encapsulated in poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) using the solution enhanced dispersion by supercritical fluids (SEDS) technique. The release tests were performed using encapsulated complex with solute loading from 2.24 to 27.5% and encapsulation efficiency from 7.75 to 55.54%. The release profile assays were performed in ethyl acetate, n-hexane and anhydrous ethanol, and monitored by UV-vis spectrophotometer concentration analysis. Results indicated higher initial release rates in ethyl acetate and in n-hexane, with cumulative release percentage varying from 31.50 to 69.58% and from 42.08 to 55.96%, respectively. For anhydrous ethanol the maximum concentration was reached at 180 min, 300 min and 10 days, depending on the initial amount of -carotene, with cumulative release ranging from 45.27 to 88.22%. In general, the -carotene release can be controlled by the organic solvent used and by the initial amount of solute encapsulated, aspects that help the selection of the conditions to achieve the desired release profiles for a specific application.
Supercritical antisolvent precipitation from an emulsion: β-Carotene nanoparticle formation
The Journal of Supercritical Fluids, 2009
Supercritical antisolvent precipitation of -carotene from an oil-in-water emulsion in which the solute is dissolved in the droplets that confirm the dispersed phase has been studied, with the objective of producing particles with a mean particle size in the nanometer scale. The aim of the current research work was to confirm the possibility to control the particle size of the carotene + surfactant suspensions obtained with this process, with the initial drop size present in the emulsions. The final products were formed by particles with a mean size below 400 nm in suspension in an aqueous media, which was also the mean droplet size of the emulsion. This result suggests that produced particles are encapsulated in surfactant micelles. The final suspension was then lyophilized and observed by means of a scanning electron microscopy. In order to obtain a better comprehension of the process, a mass transfer model was developed. This model is based on previous observations of the evolution of the organic phase drop and the solute, obtained with a view cell.
Food Hydrocolloids, 2014
b-carotene is one of the most common pigments in nature. The application of b-carotene as natural colorant in food and nutraceutical products requires an appropriate formulation in order to protect the active compound from degradation and overcome the low bioavailability due to a low solubility in aqueous media. This work presents a study of the formulation of b-carotene using four different modified n-octenyl succinate (OSA) starches as carrier materials by precipitation from a pressurized ethyl acetatein-water emulsion. The best results, with encapsulation efficiencies of 70e80% and particle sizes in the sub-micrometer range, were achieved using a OSA-starch refined from waxy maize at concentrations of at least 100 g L À1. Moreover, experiments using ethanol instead of ethyl acetate as organic solvent have been carried out in order to assess the influence of the emulsification, solvent displacement and antisolvent precipitation processes on product characteristics. Equivalent particle sizes were obtained in experiments with ethanol, but with encapsulation efficiencies below 40%, indicating that the formation of an emulsion template is essential in order to achieve a high encapsulation efficiency, while particle sizes are determined by antisolvent precipitation processes.
Biotechnology Progress, 1991
Solids precipitation from liquid solvents, with dissolution by high-pressure COz as an antisolvent to create supersaturation, is a potentially attractive crystallization process. Solids can be recrystallized and easily isolated from the liquid solvent. The gas antisolvent solvent (GAS) process was used to separate and purify &carotene from a mixture containing carotene oxidation products. Total 8-carotene was successfully separated from oxides, and an enriched trans-@carotene was obtained from its cis isomers. The separation was carried out in both batch and continuous modes. Relative solubility of the analytes and the antisolvent (COZ) have a dramatic influence on the absolute yield and purity of the product.
Engineering Journal, 2018
The crystallization of -carotene through supercritical antisolvent process with carbon dioxide (CO2) as an antisolvent has been demonstrated. The experiments were conducted at temperatures of 40-60 o C and pressures of 10-14 MPa at a constant CO2 flow rate. As a starting material, -carotene powder was dissolved in dichloromethane (DCM). Results of UV-vis spectrophotometry and GC-MS analysis showed that there was no remaining DCM solvent in the -carotene particles products. It showed that CO2 has successfully removed DCM from -carotene particles products. The product characterization by using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) showed that the CO2 solvent did not impregnate to the -carotene particles products. Results from scanning electron microscope (SEM) images showed that the -carotene particles products were successfully prepared in plate-like shape morphologies with size around 1 m.
The Journal of Supercritical Fluids, 2006
Carotenoids such as -carotene are gaining interest in the food industry due to their nutritional and antioxidant properties. Understanding the solubility behavior of carotenoids in supercritical CO 2 (SC CO 2 ) is fundamental for any industrial supercritical process application and design. Solubility of -carotene was measured in both a binary and a multicomponent complex system. Solubility of -carotene in the binary system was measured using a quartz crystal microbalance technique at temperatures of 40 and 50 • C and pressures ranging from 120 to 200 bar. Solubility of -carotene in the multicomponent complex system was determined from dynamic extraction experiments using a laboratory-scale supercritical extraction system. Carotenoids were extracted from freeze-dried carrots with SC CO 2 at temperatures of 40 and 50 • C and pressures ranging from 120 to 327 bar. -Carotene solubility values for the binary system measured herein and reported in the literature are of the order of 10 −7 mole fraction while the solubility values for the multicomponent complex system (-carotene extracted from carrots with SC CO 2 ) under the same conditions are 5-10 times smaller. Solubility in both systems increased with temperature and pressure. The difference in the solubility values obtained using both systems is mainly due to the matrix effects of the multicomponent complex system such as the cell structure and the interactions of -carotene with other components such as carbohydrates in the carrot matrix.
RPS Pharmacy and Pharmacology Reports
Objectives Carotenoids are increasingly explored as nutraceuticals but their low bioavailability due to poor aqueous solubility limits their applications. This study discusses the development of a novel and organic solvent-free method to develop carotenoid-containing polymeric nanoparticles via temperature-induced phase transition (TIPT) of pluronic F-68 to obtain formulations with the improved dissolution of carotenoids. Methods The nanoencapsulation of carotenoids in pluronic F-68 was performed in supercritical carbon dioxide (scCO2) to avoid oxidative or temperature/solvent-induced degradation. The nanoencapsulates were prepared in scCO2 at 40 or 60 °C and 10 MPa without the aid of any organic solvent. The formulations thereafter were characterised for particle size via dynamic light scattering (DLS), particle morphology via Scanning Electron Microscopy (SEM) and carotenoid content/release via high-performance liquid chromatography (HPLC). Key findings HPLC results showed caroten...