Ultrasound-assisted extraction of bayberry tannin and optimization using response surface methodology

The extraction of bayberry tannins has potential to maximize the utilization a forest waste. This study employed four-level central composite design through response surface methodology optimize tannin from barks ultrasound-assisted (UAE). effects solute solvent ratio (STSR), concentration (SC), time (ET), and sonication temperature (ST) on total yield condensed (TCT yield) phenolic content (TPC) were investigated. extracts characterized with matrix-assisted laser desorption-time flight mass spectrometer (MALDI-TOF MS), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC). optimized condition was reached when STSR ST set at 1:57.16 g/mL 71.3%, ET 39.1 min 48.75 °C. In these conditions, TCT TPC their maximum values 17.55% 365.01 mg GAE/g, respectively. Furthermore, polyflavonoids ranged dimers heptamers, which only composed proanthocyanidins (PC) containing galloy groups.