Optimized Extraction Conditions and Characteristics Analysis of Insoluble Dietary Fiber from Pomelo Peel

In order to obtain the preparation process and adsorption characteristics of insoluble dietary fiber from pomelo peel using composite enzyme method, the orthogonal test was used to optimize the extraction of insoluble dietary fiber from pomelo peel, and its characteristics were studied. The results showed that the optimal extraction conditions were as follows, material-liquid ratio of 1:40 g/mL, amylase addition amount of 0.6%, amylase hydrolysis time of 90 min, papain addition amount of 0.2% and papain hydrolysis time of 30 min. Under these conditions, the yield of pomelo peel IDF was 55.07%. The swelling capacity, water holding capacity, oil holding capacity and cation exchange capacity of pomelo peel IDF were 2.84±0.09 mL/g, 12.54±0.11 g/g, 1.54±0.02 g/g and 0.36±0.04 mmol/g, respectively. In addition, in vitro adsorption capability test indicated that the adsorption capacity of pomelo peel IDF for glucose, cholesterol and sodium cholate was 0.13±0.003 mmol/g, 12.27±0.020 mg/g and 53.25±0.100 mg/g, respectively. FT-IR results showed that pomelo peel IDF had characteristic absorption peaks of cellulose polysaccharides, which was consistent with the structure of dietary fiber. In summary, the extracted pomelo peel IDF exhibited good characteristics after optimizing the process. It can provide theoretical basis for the development and utilization of pomelo peel IDF.