Optimization of Ammonium Oxalate Extraction of Pectin from Sweet Potato by Response Surface Methodology

Response surface methodology was applied to establish the optimal conditions for pectin extraction from sweet potato residues left after starch extraction using ammonium oxalate as the extraction solvent.Extraction at 95.07 ℃ for 1.93 h with 5.0 mg/mL ammonium oxalate at pH 5.8 proved optimal.The maximum predicted yield and purity of pectin under the optimized conditions were respectively 11.36% and 76.68% versus 11.19% and 79.95% obtained in validation experiments.This close agreement between the experimental and model predicted results indicates the mathematical model is valid for predicting the extraction of pectin from sweet potato residues.