| Potato pulp is one of the main by-products in potato starch processing. The wet slurry with high water holding capacity is not convenient drying, and easy to fermentation on the production season, and then cause environmental pollution. Generally, potato pulps were treated as fodder for animal or as a fill in farmland. These methods can not effectively settle the massive accumulation of potato residue, and transportation cost is high. In this paper, potato pulp was treated by wet ultrofine grinding, which improve the the rough taste of potato residue and the functional properties. Moreover, the homogeneous slurry achieved can be dried easily by various dring equipment and is conducive to the preservation of potato residue. Then the modified potato pulp rich in Dietary fiber can be applicated in food industry as functional food ingredients. As a result, the utilization value of potato pulp is improved. In this paper, the results are as follows:First of all, colloid mill is used as a ultrofine grinding equipment to treat potato pulp. The morphological infrared spectroscopy and X-ray diffraction scanning changes of potato pulp treated with colloid mill. Meanwhile, infrared spectroscopy and X-ray diffraction scanning were used to test the changes of potato pulp insoluble dietary fiber (PIDF), the results showed the degradation of potato pulp cell wall structure , the enhancement of hydrophilic ability and the slightly decrease of relative crystallinity in PIDF. It also proved that a ultrafine powder with an average particle size of less than 100μm can be achieved when the colloid grind clearance at 12μm. At this point, the potato residue particles pose larger specific surface area, the smallest density of 0.22 g / ml and the most loose network structure. In conclusion, modified potato pulp can be achedved by colloid mill.Secondly, the water solubility, swelling and water retention capacity and viscosity of potato pulp , PSDF and PIDF treated by colloid mill in different colloid grind clearance was studied. The research shows that the treatment of potato pulp by colloid mill can change insoluble fiber ingredients into soluble components. As the grinding clearance decreased, the residue solubility increased from 14.12% to 21.52% by 52.4%. The modified residue get the best swelling and water retention capacity reached 9.42 ml / g and 7.21 g / g increase by 38.1% and 42.5% respectively when at 12μm grinding clearance. Heat treatment in food processing will greatly increase the physical property. At the same time, colloid mill treatment can effectively increase the viscosity of potato pulp, PIDF and PSDF. As colloid grinding clearance decreased, potato pulp showed viscosity property that barely existed before, and the viscosity increased from 11mPa.s to 108mPa.s by 881.8%.Moreover, The physicochemical properties relative to hypoglycemic and decreasing serum lipids functional properties of potato pulp, PIDF and PSDF after colloid mill treatment at different grind clearance were studied. The physicochemical properties includes bile sodium adsorbabilty, oil holding capacity, cation exchange capacity, pancreatic lipase activity inhibitory, glucose absorption capacity andα-amylase inhibitory activity. The result revealed that both PIDF and PSDF had certain functional properties and there was a Synergistic Effect between them to improve the properties of modified potato pulp. In decreasing serum lipids side, the modified potato residue has a bile sodium adsorbability of 13.44 mg/ g, oil holding capacity of 7.26 g / g, cation exchange capacity of 512 mmol / kg, pancreatic lipase inhibitory activity of 67.2 %, increased 41.03%, 45.8%, 23.7% and 39.7% respectively than the production without treatment; In hypoglycemic side, the related characters of the modified pulp were improved. The golucose absorption capacity had a maxium increasement by 68.4 %, and theα-amylase inhibitory activity had a maxium increasement by 81.0 %, the absorption capacity and inhibitory activity were 0.682 mmol / g and 28.6%. Hypoglycemic in nature, the study showed that glucose modified potato residue on capacity constraints and the amylase inhibition of both the former than the increase in glucose concentration was 100 mmol / L, the largest increase 68.4 percent, while the amylase Suppression of the largest increase 69.6 percent, the shackles of force and suppression were 0.682 mmol / g and 28.6%. The porous structure of modified potato pulp and its large specific surface area plays an important role in these features. In general, a product with better physical and chemical nature was obtained with colloid mill treatment at the gind clearance of 12μm.Finally, the optimum modified potato residue was added to different gluten content flours, Then rapid viscosity analyzer (RVA), farinograph and extensograph were applied to test the change of the dough rheology. The results showed that the pasting curve can be used to judge the quality of different flours. A higher gluten content flour is company with lower peak viscosity and pasting temperature. The addition of modified potato residue dilutes the gluten and starch content of flours, which lead to the downward of the pasting curve overall, including the decreasement of peak viscosity, breakdown, setback and final viscosity. As a result, the heat-resistant stablilty of flours is increased while the retragradation degree is reduced relatively. Simultaneity, the interaction of potato residue fiber and gluten accelerate the water absorption ability of the dough but worsene the quality, so that the formation and stability time is shorted and the degree of softening is increased. The modified residue was added to cookies at last. The test showed that the storage period is extended by the addition of modified potato pulp. it's due to that the pulp can inhibite the loss of flavor, delay the increasement of hardness and prevent the oxidation of oil in cookies. The addition of modified potato pulp by 10% is supposed to have a similar taste as the control. With the prolonging of storage period, the cookies shows nicer sensory quality than the control.
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