Optimizing the Alcohol Precipitation of Danshen by Response Surface Methodology

Abstract

Alcohol precipitation (AP) is a common method to achieve separation and purification in the process of food and herbal preparations. The response surface methodology (RSM) was applied to study and optimize the AP of Danshen, regarding the recovery of danshensu (RD) and the removal of saccharides (RS). A fractional factorial design was initially performed and solid content, ethanol consumption, acid consumption, and temperature showed significant influence on RD and RS. A Box-Behnken design with 28 experimental runs was then applied and two polynomial equations were established, based on which the effects of significant factors and their interactions were discussed. The optimum operating conditions were solid content at 66.0%, ethanol consumption at 4.3 mL/g, acid consumption at 0 g/g, and temperature at 10.7°C. The average experimental RD and RS under the optimum conditions were obtained to be 66.25 ± 1.01% and 61.64 ± 1.84%, respectively, which agreed well with the predicted values (68.85% for RD and 61.92% for RS).