Abstract:The objective of this reasearch was to evaluate the effects of potato pulp dietary fiber under cellulase，xylanase and the composite process of cellulase and xylanase on the physicochemical properties and monosaccharide composition.The constituent monosaccharides of potato residue dietary fiber by different enzymatic treatment were identical，namely glucose，galactose，galacturonic acid，arabinose and xylose，despite a significant difference in there percentages（p＜0.05）.The results of physicochemical properties showed that water holding capacity，water binding capacity and solubility of dietary fiber modified by different enzymatic methods were in the decreasing order of complex enzyme modification，xylanase modification，cellulase modification.The decreasing order of oil holding capacity and cation-exchange capacity were compound enzyme modification，cellulase modification，xylanase modification.After the potato residue dietary fiber was modified by compound enzyme，the water holding capacity，oil holding capacity，water binding capacity，solubility and cation-exchange capacity of the dietary fiber reached 6.29 g/g，2.89 g/g，5.99 g/g，32.28%，0.60 mL/g，increased by 115.22%，16.73%，27.18%，45.27% and 173.18%，respectively.The dietary fiber had the characteristic absorption peaks for carbohydrates before and after modification，and the ab-sorption peaks were similar at some wavelengths，except that the intensity and area had changed of the absorption peaks.