A Box-Behnken design was employed to study the combined effects of variables of microwave-assisted extraction on pectin from sugar beet pulp. The independent variables were time and power of microwave-assisted extraction, pH of sulfuric acid and rate of solid to liquid (SLR). The combined effects of these variables on degree of esterification (DE) were studied. Results have shown that the generated regression model significantly explained the actual relationship between the independent variables and response. Besides that, pH was the most important variable which affected the DE. Higher acid concentration, extraction power and longer extraction time increased the DE of pectin due to Esterification. Through the response surface, the satisfactory conditions for extraction of high-ester sugar beet pulp pectin were obtained as follows: 1.02 of pH, 3.96 min of extraction time, 193.68W of power and 19.98 of SLR.

Deqiang Li, Jianjiang Shang, Xinfang Ma, Xiaoyan Zhu and Zhiyong Liu