Successive concentrations of phenolic compounds of ‘Yerba Mate’ (Ilex paraguariensis) and their contribution to antioxidant capacity

Four successive concentrations of yerba mate extract were made at 30, 50 and 70 °C, adding new yerba mate at the beginning of each concentration. The content of total phenolic compounds (TPC) was evaluated with the Folin-Ciocalteu method and the antioxidant capacity (AOC) with the DPPH (2.2-diphenyl-1-picrylhydrazyl) free radical assay.The results of this work showed that TPC increased significantly with increasing temperature, while AOC decreased (p<0.05). The TPC extracted was highest at 70 °C, obtaining a value of 38.06 ± 1.56 g EAG/L, and at 30 °C 25.50 ± 0.14 g EAG/L was obtained. The AOC showed a decreasing trend with increasing temperature. Values ranging from 94.39 ± 0.65 g EAA/L at 30 °C to 52.53 ± 0.09 g EAA/L at 70 °C were obtained. For the four times concentrated extracts, the values were (39.33 ± 6.71) % (TPC) and (28.48 ± 0.99) % (AOC) higher than those of the non-concentrated extracts. We conclude that the successive extraction technique provides, by increasing the number of extractions, an effective way to produce extracts rich in polyphenols and high antioxidant capacity using moderate temperatures during the extraction process, avoiding thermal degradation of the extract.