Microwave-assisted extraction of phenolic compounds from coffee (Coffea robusta L. Linden) bee pollen

Abstract

Summary: Introduction: Coffee bee pollen contains some precious bioactive compounds, especially phenolic compounds. This material is easily found in many regions in Vietnam and is quite useful for human health. Objective: The main aim of this study was to determine the best extraction conditions for the total polyphenol content (TPC) and antioxidant capacity (AC) of coffee (Coffea robusta L. Linden) bee pollen with microwave-assisted extraction (MAE). Methods: TPC and AC of extract of coffee (C. robusta) bee pollen were determined using Folin-Ciocalteu (FC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, respectively. In addition, micromorphology of sample was observed using scanning electron micrographs (SEM). Results: The findings showed that all factors strongly affected the efficiency of the extraction process. The best extraction conditions obtained were ethanol concentration of 60% (v/v), solid to solvent ratio of 1/30 (w/v), extraction time of 7 min, and a microwave power of 314 W. Conclusion: The highest TPC and AC obtained were 13.73 mg GAE/g DW and 10.08 μmol TE/g DW with aqueous ethanol as the solvent at the optimal extraction condition. In addition, the microstructures of the material changed insignificantly under microwave irradiation.