Abstract:

Objective: The optimization of the extraction process of phenolic compounds from Robinia pseudoacacia L.flowers under ultrasound assistance was achieved by response surface methodology to maximize phenolic extraction yield. Methods: On the basis of single-factor experiments, Box-Behnken central composite design (CCD) involving four variables at three levels was utilized to set up a quadratic polynomial regression equation for phenolic extraction yield as function of extraction temperature, ultrasound power, length of ultrasound treatment time and material/liquid ratio, and the pairwise interactive effects of the above four variables on their function were investigated by response surface analysis. Results: The optimum conditions for extracting phenolic compounds from Robinia pseudoacacia L.flowers were found to be: 36 min ultrasound treatment at 110 W power for extracting the raw material with a 20-fold volume of 60% aqueous ethanol solution at 35 ℃. Under these optimum conditions, the yield of polyphenols was 7.891%.

Key words: Robinia pseudoacacia L. flowers, phenolic compounds, response surface methodology