Antioxidant activity of microparticles obtained from beet leaf extracts (Beta Vulgaris L.) using supercritical atomization assistance (SAA)

Despite their characteristic value, Beet leaves are generally underutilized or discarded as waste. This agro-industrial waste can be used as a source of bioactive compounds, and its recovery adds value to the processing chain. This study aimed to evaluate the antioxidant activity of microparticles obtained from beet leaf extract (Beta Vulgaris L.) using supercritical assisted atomization (SAA). The extract was obtained using a sample ratio of 1:40, with 70% ethanol as the solvent, for 2 hours. The operating conditions for each test applied to the SAA were aprox. 30.0 s of CO₂ flow, aprox. 50.0 s of solvent flow, and a ratio of 1:10 (extract/polymer) for SAA 1; aprox. 35.0 s of CO₂ flow, aprox. 50.0 s of solvent flow, and a ratio of 1:20 (extract/polymer) for SAA 2; aprox. 40s of CO₂ flow, aprox. 60s of solvent flow, and a ratio 1:30 (extract/polymer) for SAA 3. The antioxidant activity of the microparticles was determined by their ability to inhibit the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results showed that the extract encapsulated with PVP (polyvinylpyrrolidone) had better antioxidant activity than the pure extract. The results indicated that the antioxidant activity obtained in the SAA 3 treatment was higher than the other treatments, with approximately 53 µmol TEAC.g^-¹. This may indicate that the increase in antioxidant activity is related to a higher proportion of PVP. This is demonstrated by the results observed in all treatments, where antioxidant activity increases as the proportion of PVP increases. Therefore, the encapsulation technique using SAA has proved to be a promising technology for the utilization of beet leaf, contributing to the development of the circular economy.