Optimization of intermittent microwave extraction method for the determination of pectin from pomelo peels

The process of intermittent microwave extraction (IME) pectin from pomelo peels assisted with EDTA was optimized by response surface methodology. Results showed that the optimal process for intermittent microwave extraction of pectin was as follows: 0.25% EDTA, pH 1.0, solid-to-liquid ratio 1:25 gml(-1), extraction time 125 s, microwave power 550 W, the extraction yield of pomelo peels was (38.48 +/- 0.28)%. The structure of three kinds of pectin was verified by IR, SEM, XRD, HPLC and the results showed that pectin obtained from IME had a poor solubility but a good emulsifying activity. The IUEP had the highest scavenging rates of DPPH radicals.