Study On Production Technology Of Potato High-quality Dietary Fiber

Potato pulp is the waste residue produced during potato starch produce porcess,and the potato pulp contains a lot of dietary fiber accounts for about50%of the dry basis.But because the concentration of production season,a lot of potato pulp was produced,which was not easily transported and stored,corrupt potato pulp can produce the stench and cause environmental pollution.In order to make full use of potato pulp,this article use twin-screw extrusion technology to potato pulp for modification,increase the content of soluble dietary fiber,and the potato high-quality dietary fiber was obtained,the infrared characterization,the matter properties and monosaccharide composition were analyzed. In addition,extrusion technology improve the rough taste of potato pulp,which could be applied to food in dustry,not only can solved the problems such as pollution,but also reduced the cost of potato starch production. The main research results in this article were as followed:1. The potato pulp was used as raw material and enzymolysis was applied to remove the starch to obtain potato dietary fiber.The composition of potato dietary fiber was determined. The results showed that cellulose content was33.07%,hemicellulose content was38.79%,lignin content was1.97%,pectin content was17.95%and other was8.22%.2. Twin-screw extrusion technology was applied to modify potato dietary fiber to make potato high-quality dietary fiber.The optimal extrusion condition was obtained by response surface methodology:potato dietary fiber size was0.175mm,moisture content was141%,and extrusion temperature was172℃,on this condition,the content of potato soluble dietary fiber was25.99%.Sequence of factors influencing soluble dietary fiber content was moisture content> extrusion temperature> size.3. The matter properties of potato dietary fiber and potato high-quality dietary fiber were studied.The results showed that the holding oil power of potato dietary fiber was1.90g/g,the holding water power was7.00g/g and the expansive power was7.37mL/g.The holding oil power of potato high-quality dietary fiber was5.17g/g,the holding water power was8.34g/g and the expansive power was9.91mL/g. The polymerization degree of potato dietary fiber extruded by twin-screw decreased from1051to273and the molecular weight decreased from170333to44226.The matter properties of potato high-quality dietary fiber was better than those of potato dietary fiber.4. The potato dietary fiber and potato high-quality dietary fiber were observed from microstructure level.The results showed that the structure of potato dietary fiber was relatively tight and presented flaky texture and the surface was flat and smooth. While potato high-quality dietary fiber was loose,folded,more conducive to water to infiltrated and bound.Therefore,the holding water power,expansive power and holding oil power of potato high-quality dietary fiber were increased.5. The infrared characterization of potato dietary fiber and potato high-quality dietary fiber were analyzed.The results showed that potato dietary fiber and potato high-quality dietary fiber contained the characteristics of carbohydrate absorption peak,such as C=O、C-H、COOR,free hydroxyl groups,etc.Monosaccharides had pyran ring structure,and both of the two kinds of soluble dietary fiber had uronic acid and carboxylic acid dimer.6. Monosaccharide composition of soluble and insoluble dietary fiber fraction in potato dietary fiber and potato high-quality dietary fiber were analysed.It was founded that arabinose,xylose and glucose existed in potato dietary fiber and potato high-quality dietary fiber. Both of the two kinds of insoluble dietary fiber contained galactose.Moreover,potato high-quality soluble dietary fiber contained rhamnose and galactose.7. Potato high-quality dietary fiber was added into bread as food accessories.It was based on flour weight to other accessories.By response surface methodology,the best formula of potato high-quality dietary fiber bread was as followed:potato high-quality dietary fiber content was4.3%,water content was55%,butter content was6.15%,soft sugar content was12%,yeast content was2%,egg content was6%,bread improver content was1.97%and salt content was1%, the specific volume of bread was6.01mL/g,hardness was1785.238,spring was0.897,resilience was0.281and chewiness was1149.660.The spring and resilience was better.The taste of bread was good and it had special aroma of baked goods.