Journal of Supercritical Fluids, Vol.137, 81-92, 2018
Co-precipitation of anthocyanins of the extract obtained from blackberry residues by pressurized antisolvent process
An ethanolic anthocyanin-rich extract was obtained from blackberry residues through ultrasound assisted extraction, and extracts were co-precipitated with the biodegradable polymer polyvinylpyrrolidone (PVP) through the supercritical antisolvent process (SAS), using carbon dioxide as antisolvent. The influence of temperature (30-45 degrees C), PVP concentration in the extract (0.5-4.0%) and solution flow rate (1-10 mL/min) on the SAS process were investigated. The decrease of these three parameters contributed to produce particles with smaller diameter, residual ethanol, humidity and water activity, although with higher hygroscopicity. Moreover, the increase of these parameters intensified the agglomeration of the particles. SEM images revealed co-precipitates with irregular shapes obtained at high temperatures, flow rates and PVP concentrations. FTIR analysis showed that neither extract nor PVP properties were modified in the SAS process. Good precipitation yields were achieved, indicating that the SAS process is effective and selective in the co-precipitation of anthocyanins.