Abstract: The extraction of polyphenols from Chinese prickly ash was optimized for increased yield of polyphenols. The influence of temperature, extraction time, solvent concentration, solid-to-solvent ratio and pH on extraction efficiency was investigated initially by one-factor-at-a-time method. Using the Box-Behnken response surface methodology, the optimum extraction conditions were obtained as follows: 48.23% (V/V) acidified ethanol (pH 3) as extraction solvent, solid-to-solvent?ratio 1:29.34 (g/mL), temperature 48.99 ℃, and extraction time 1.75 h. Under these optimized conditions, the average yield of polyphenols reached 55.06 mg/g (n = 5). In addition, the mass transfer kinetics during the extraction of polyphenols at different temperatures was investigated. Based on Fick’s first law of diffusion, a kinetic equation was established with the plate model. The key model parameters, including rate constant, relative extraction rate and activation energy, were obtained. These results could provide a theoretical basis for industrial extraction and further study of polyphenols from Chinese prickly ash.

Key words: Chinese prickly ash, polyphenols, extraction, response surface analysis, kinetics