Recovery of bioactive components from avocado peels using microwave-assisted extraction

Abstract The avocado processing industry generates large amounts of avocado peels, which contain large amounts of high value-added compounds with antioxidant capabilities that have not yet been explored. Optimization of microwave-assisted extraction (MAE) of bioactive compounds from avocado peels with high antioxidant capacity was the objective of present work. Two experimental designs were implemented, using acetone 70% and ethanol at different concentrations, finding at 74.48 °C by 14.32 min and 66.37 °C by 0.97 min with 42.58% of ethanol as optimal conditions to obtain the highest antioxidant capacity, respectively. Optimized extracts with acetone and ethanol showed a high polyphenolic content (379.28 ± 19.35 and 354.43 ± 16.85 mg GAE/g dry extract, respectively); high antioxidant activity measured by DPPH (268.04 ± 25.11 and 233.85 ± 13.58 mgET/g dry extract, respectively); ABTS (895.19 ± 30.41 and 949.41 ± 7.42 mgET/g dry extract, respectively); ORAC (648.88 ± 28.66 and 692.06 ± 28.80 mgET/g dry extract, respectively), results reported for the first time. Fiber bonded phenolics compounds was extracted of MAE residues show a significant antioxidant activity. HPLC-MS analysis of optimized extracts showed the present of diverse phenolic acids, numerous procyanidins dimer A and B in different isomer shapes, catechin, epicatechin and perseitol.