Bioactive compounds from Dioscorea bulbifera L. obtained by combined ultrasound- assisted and solid-liquid extraction

Abstract

Abstract The aim was to extract bioactive compounds from the husk and pulp of Dioscorea bulbifera L. by the combination of ultrasound and solid-liquid extraction techniques, as well as to evaluate the antioxidant potential. The extraction at 80°C for 60 minutes showed the highest content of total phenolic compounds (TPC), 715.53 ± 8.00 mg EAG 100 g− 1, for the husk, while the extraction at 70°C for 45 minutes showed 235.50 ± 25.30 mg EAG 100 g− 1, for the pulp. The extracts with the highest TPC were evaluated for the other bioactive compounds. The husk and pulp extracts showed flavonoid content of 363.63 ± 8.92 and 102.44 ± 1.51 mg EC 100 g− 1, respectively. The estimation of the total carotenoid content allowed obtaining 2.13 ± 0.11 µg 100 g− 1 for the husk and 1.34 ± 0.11 µg 100 g− 1 for the pulp. The antioxidant potential was evaluated according to the FRAP assay (125.09 ± 8.52 and 32.76 ± 0.65 µM ferrous sulfate g− 1), the removal of H2O2 (29% and 41%), the ABTS radical assay (66.88 ± 0.93 and 14.93 ± 0.31 µM Trolox g− 1) and the β-carotene/linoleic acid system, (84% and 47%) for husk and pulp, respectively. The bioaccessibility was obtained around 25% (pulp) and 16% (husk) accessible for absorption in the intestine. The combination of ultrasound and solid-liquid extraction methods proved to be effective in extracting bioactive compounds, which is a potential source for isolation and purification of bioactive compounds, with possible applications in the food industry.