Abstract: Acid extraction followed by ethanol precipitation was used to extract pectin from citrus peel in the present work. Four factors that affect the extraction yield of pectin including material-to-liquid ratio, temperature, extraction time and pH were systematically investigated by one-factor-at-a-time method and response surface analysis. Further, the four factors were optimized and their significance was analyzed. As a result, the optimal conditions for pectin extraction were determined as follows: material-to-liquid ratio 19.7:1, temperature 87.5 ℃, extraction time 84 min, and pH 1.51. Under these conditions, the actual pectin yield was 7.294%, which was close to the predicted value of 7.316%. Thus, the optimized process can provide useful guidance for industrial pectin preparation.

Key words: response surface methodology (RSM), citrus peel, pectin, extraction