Abstract:Ultrasonic-assisted enzyme-alkali combination method was used to extract potato dietary fiber from potato by-products.Single-factor test and response surface test were applied to optimize the extraction conditions.The optimal extraction process was determined as followed：ultrasonic power was 180 W，the ultrasonic temperature was 50℃，the addition amount of α tmylase was 2%，the digestion time was 35 min，the NaOH concentration was 3%，and the alkaline hydrolysis time was 14 min，under this condition，the dietary fiber extraction rate could reach 66.56%.The physical and chemical analysis method were used to determine the quality characteristics of the extract.The results were as follows：the total water holding capacity of the dietary fiber was 9.02 g/g，the oil holding capacity was 1.3 g/g，the swelling power was 3.5 mL/g，and the cation exchange capacity was 0.72 mmol/kg，glucose adsorption capacity was 137.2 mg/g，cholesterol adsorption capacity was 9.54 mg/g and 16.82mg/g，when pH was 2and 7，respectively，and nitriteion adsorption capacity was 7.31mg/g.