Optimization of Extraction Process and Purification of Flavonoids from Peony Seed Meal by Membrane Method

In this study, the flavonoids in peony seed meal were separated and purified by microfiltration-nanofiltration secondary membrane separation method. The effects of material-liquid ratio, extraction temperature, ethanol volume fraction and extraction time on the extraction amount of total flavonoids were investigated by single-factor experiments, and the extraction process was optimized and validated by response surface methodology on the basis of single factors. Eight types of microfiltration membranes, including polyvinylidene fluoride (PVDF), polyethersulfone (PES), polytetrafluoroethylene (PTFE), polypropylene (PP), mixed cellulose (MCE), polyacrylonitrile (PAN), aqueous acetate (CA) and polyamide (PA), were selected for the primary separation of PSMF extracts. The nanofiltration membranes were homemade organosilicon/PA composite membranes in the laboratory. The results showed that the optimum extraction conditions for PSMF were 1:15 g/mL, 50 ℃, 70% ethanol volume fraction, 30 min, (240.28±2.25) μg/mL of PSMF extraction amount. The PA membrane had a better separation effect, and the composite membrane had a better purification effect on PSMF, and the water solubility of flavonoids was increased to more than 90% after separation. After calcination at 800 ℃, the residual mass of the raw material solution was 1.43% and that of the PA membrane separation was 0.76%, and the BTESE/PA composite membrane was reduced to 0.26%, with fewer impurities and higher purity. Comparing its antioxidant activity before and after separation, the ·OH, DPPH· scavenging rate and reducing power were improved after separation, and the O2−· scavenging rate decreased from 79.94% to 64.82%. In this study, the active components in peony seed meal were analyzed. PSMF would be a novel phytoflavonoid resource with rich composition and certain research space.