phd juliana

Concentration of bioactive compounds from blueberry (Vaccinium myrtillus L.) waste using supercritical CO2 extraction and nanofiltration

Author: Juliana Paes (2016)

Abstract: This work explored the advantages of using supercritical carbon dioxide and pressurized liquids in the extraction of bioactive compounds from dry and fresh blueberry (Vaccinium myrtillus L.) residues. In pressurized liquid extraction liquids water, acidified water and ethanol were used as solvents at different ratios, but with temperature, pressure and flow rate constant at 40 °C, 20 MPa and 10 mL/minute, respectively. The extracts were analyzed and best conditions found with pressurized ethanol and water + ethanol, for phenolic compounds and antioxidant capacity. Anthocyanins were identified in greater amounts in the samples extracted with acidified water. In supercritical fluid extraction, different ratios of CO2, water, acidified water and ethanol were used, and the best condition was found in the experiment with 90% CO2, 5% water and 5% ethanol, due to the higher concentrations of phenolic compounds, antioxidants and anthocyanins in the extract. The spectrophotometric method for the quantification of anthocyanins showed higher concentrations compared to those obtained by ultra performance liquid chromatography (UPLC). Next, the extracts obtained at the conditions with increased yield of these compounds, and the blueberry residue, were subjected to nanofiltration. Among the tested membranes, the nanofiltration membrane NF 270 achieved higher retention of phenolic compounds, antioxidants and, specifically, the retention of anthocyanins was greater than 90% when evaluated by both differential pH and UPLC methods.