Optimization Of Modification Process And Research On Structure And Property Of The Tillering Onion Dietary Fiber

In order to study the effect of modification treatment on the structure,physicochemical and functional properties of Tillering Onion dietary fiber.The Tillering Onion was used as the main raw material,and the Tillering Onion was modified by extrusion modification and cellulose enzymatic modification.Determination of Tillering Onion dietary fiber Structure by Infrared Spectroscopy,X-Ray Diffraction,and Electron Microscopy.To study the effect of modification treatment on the physicochemical and functional properties of Tillering Onion dietary fiber.This study provides a theoretical basis for the application of Tillering Onion dietary fiber in food deep processing.The main contents and results were as follows:（1）The use of single-screw extrusion technology to modify Tillering Onion dietary fiber can improve the extraction rate of water-soluble dietary fiber from Tillering Onion.It analyzes the effects of extrusion temperature,particle size,and moisture content on the yield of SDF by single factor tests,and optimizes the process using response surface methodology.The best process parameters for extrusion was perature 140℃,80 mesh material particle size,water content of 35%.Under the optimal conditions,SDF was exported（13.94±0.14）%.It is 2.4times the extraction rate of unmodified Shallot onion SDF.The factor sequence of influence exporting SDF was extrusion temperature>water content>material particle size.（2）The use of cellulase to modify Tillering Onion dietary fiber can increase the extraction rate of water-soluble dietary fiber from Tillering Onion.Through single-factor tests,the impact of cellulose enzyme additives,solution pH,reaction temperature and reaction time four factors on the yield of SDF was analyzed.And the process was optimized by orthogonal test.The best process parameters for enzymatic modification was cellulose enzyme addition amount 2.5%,solution pH 5.5,reaction temperature 50℃,reaction time 5 h.Under the optimal conditions,SDF was exported（13.83±0.11）%.The factor sequence of influence exporting SDF was cellulose enzyme additives>solution pH>reaction temperature>eaction time.（3）This research adopts the electron microscope scanning,Infrared Spectroscopy and X-ray diffraction analysis of modified treatment effects on Tillering Onion dietary fiber structure.The results of scanning electron microscope show:The modification process makes the Tillering Onion dietary fiber structure become loose,more honeycomb pores,more wrinkles on the surface,the specific surface area of the sample increases,which is conducive to improve the adsorption of dietary fiber.The results of Infrared Spectroscopy show:The main components and chemical structures of the Tillering Onion dietary fiber structure before and after the modification process did not change significantly and changed,and all showed the infrared spectrum characteristics of the polysaccharide.The results of X-ray diffraction show:The Tillering Onion dietary fiber after modification of the cellulose characteristic diffraction peaks is much smaller than that of the unmodified Tillering Onion dietary fiber crystals.It shows that the modified treatment reduces the crystallinity of Tillering Onion dietary fiber,and allows some insoluble components to be dissolved or converted into water-soluble components to meet the requirements of high-quality dietary fiber.（4）The effects of modification treatment and particle size on the physicochemical properties and functional properties of Tillering Onion dietary fiber were studied.The results show:The extrusion modification results are superior to the results of the enzymatic modification of cellulose.Both modification methods can significantly improve the physical and chemical properties of Tillering Onion dietary fiber’s water holding capacity,oil holding capacity,swelling force and cation adsorption capacity.And they can also significantly improve the glucose absorption capacity,cholesterol adsorption capacity and NO₂^-adsorption capacity of the onion dietary fiber.Material particle size has a significant effect on the physicochemical properties and functional properties of Tillering Onion dietary fiber.At grain size of 100 mesh,Unmodified Tillering Onion dietary fiber,Extruded Modified Tillering Onion dietary fiber and Enzymatically Modified Tillering Onion dietary fiber have the best physical and chemical properties.