Pressurized liquid extraction applied for the recovery of phenolic compounds from beetroot waste

Beetroot (Beta vulgaris L.) residues, leaves and stems, normally disposed as animal feed or compost, were investigated for the recovery of valuable compounds by pressurized liquid extraction (PLE) at temperature of 40 degrees C and pressures of 7.5, 10 and 12.5 MPa, and flow rate of 3 mL min(-1). This abundant residue, combined with the lack of related studies of beetroot waste by applying the PLE methods to obtain bioactive extracts is the main novelty of this work. Then, the objective was to explore the PLE process to enhance the value of the residues, evaluating process yield, total phenolic content (TPC) and antioxidant activity (DPPH, ABTS and FRAP methods) of the recovered extracts. Chemical composition was analyzed using LC-ESI-MS/MS and GC-MS analysis. Antioxidant potential results suggest the recovered extracts are comparable with synthetic antioxidant (BHT). Ferulic acid, vitexin and sinapaldehyde, were the most abundant phenolic compounds obtained from the extracts. These results indicate that PLE technique can be a good alternative for extracting phenolic compounds of beetroot resides with high biological potential that could be used in formulations for nutraceuticals, functional food or pharmaceutical industry.