Extraction process of insoluble dietary fiber from orange peel residue

Orange peel residue after extracting pectin and hesperidin is an excellent source of water insoluble dietary fiber. In order to further implement the secondary use of orange peel residue, the preparation of IDF from the residual slag by chemical methods and its bleaching were studied. The results showed that the optimum condition of IDF extraction was 0.25mol/L of the sodium hydroxide concentration, 50℃ of the extraction temperature, 1 ∶15 of the ratio of material and liquid and extracting for 1 hour. The optimum condition of the decoloration of IDF was 4% of H2O2 concentration, 60℃ of the decoloration temperature, pH 9 and decolorizing for 3 hours. Under these conditions, the IDF yield and extraction rate were 65.98% and 92.86%, respectively, for the milky white color.