Research Lines

       The works carried out at LATESC, for the most part, benefit from the use of supercritical fluids for different applications. Supercritical fluids are substances that are in conditions of pressure and temperature above their critical values. They have properties close to those of gases, such as viscosity and diffusion coefficient, and liquids, such as density, which make them strong solvents with excellent transport properties. Furthermore, from small changes in the temperature and pressure conditions of the system, variations in these properties and in the selectivity of these solvents occur, which can be controlled in order to favor the processes.

       The most conventional supercritical fluid, which is also used by the laboratory, is carbon dioxide, which has low toxicity, is non-flammable, is easy to separate at ambient temperature and pressure, and has not very high critical parameters (31.4 °C and 7.88 MPa).

        Although not exclusive, studies performed in the laboratory generally fall within these five lines of research:

Biorefinery and Extraction of Bioactive Compounds

        The concept of biorefinery, although dynamic, involves different routes of conversion of agro-industrial biomass into two types of products, bulky materials with low added value, such as biofuels and fibers, and a small volume of compounds with high unitary value, such as bioactive compounds and chemical additives. These high added value products are of interest to the food, pharmaceutical, cosmetics and fine chemicals industries, and can be obtained through different extraction methods. In LATESC the following techniques are adopted: Soxhlet extraction (SOX); Supercritical Fluid Extraction (SFE); Extraction with Pressurized Liquid (PLE); Subcritical Water Extraction (SWE); and Microwave Assisted Extraction (MAE).

High Pressure Phase Equilibrium

        The study of phase equilibrium is carried out to predict the behavior of mixtures of known composition at certain temperatures and pressures of interest. Although thermodynamic models are also used for this function, experimental data are indispensable to fit the interaction models. Several crucial information for high pressure processes can be obtained through phase equilibrium, such as solubility data of a compound to be extracted or temperature and pressure recommendations for operating a reactor. At LATESC, experiments are carried out using the static synthetic method by visualization, studying relevant data for high pressure extraction, polymerization in supercritical media and systems in the petrochemical industry.

High Pressure Particle Formation, Encapsulation, and Impregnation

        The processes of particle formation, encapsulation and impregnation aim to modify physicochemical properties of bioactive compounds, enabling them to have a wider application and providing them with greater bioavailability, or even to enrich foods with the addition of these compounds. The particle formation methods performed at LATESC are micronization, co-precipitation and co-crystallization.

        The different processes employ the supercritical fluid as a solvent, as a solute, or even as an anti-solvent, and have advantages over conventional techniques, such as obtaining solvent-free products and the possibility of operating under mild process conditions, which minimize the occurrence of degradation of bioactive compounds.

Polymerization in Supercritical Medium

        Enzymatic polymerization in a supercritical medium allows replacing the use of metallic catalysts and organic solvents in the traditional polymerization process, making it possible to obtain products free of toxic residues. At LATESC, reactions are carried out for the formation of biocompatible, biodegradable and bioreabsorbable polymers, which have ε-caprolactone, pentadecalactone, globalide and l-lactide as monomers. Such materials are of great interest to the pharmaceutical, biomedical and food industries.

Supercritical Drying and Aerogel Formation

        Supercritical drying is a process used to obtain aerogels from biopolymers with gelling properties. Airgel is a solid material that has unique properties such as extremely low density, huge surface area and open pore structure at the nanometer scale. These materials have several applications in the pharmaceutical, cosmetic, medicinal and biotechnological areas. At LATESC, the use of these materials as additives in food is of interest, with the functions of carriers of active compounds, emulsifiers and aroma dispersing agents.

Last update: 08/2022