The Effects Of Screw Parameters On Chemical, Physical Properties And Syrup Indicators Of Degerminated Corn

The production of starch syrup by extrusion method has the advantages of low production cost,light environmental pollution and simple process.The effects of single-screw extruder's parameters for degerminated corn were studied.The diameter of choke ring,the pitch of screw,the interval of spindle and the speed of screw were taken as the influencing factors.The chemical,physical properties and syrup indicators were taken as response value.The method of quadratic orthogonal rotating combination design of four factors and five levels was used.Through the above experiments,the following conclusions were drawn:1 The effects of the diameter of choke ring,the pitch of screw,the interval of spindle and the speed of screw on the chemical properties of extruded corn were studied.The degree of gelatinization and the enzyme hydrolysability increased firstly with the increase of the screw parameters and then decreased.The starch-iodine value was decreased firstly with the increase of the screw parameters and then increased.2 The effects of screw parameters on the physical properties of extruded corn were studied.(1)Extrusion can destroy the original smooth polyhedral shape of deblasted-corn starch particles.The extruded corn was massive,rough and porous.(2)The DSC results showed that enthalpy value was increased firstly with the increase of the screw parameters and then decreased.(3)X-ray irradiation showed that the intensity of partial diffraction peak of extruded corn was lower than degerminated corn.A new diffraction peak appeared when the diffraction angle of 2 theta is 20 degrees after extrusion of different screw parameters.The results showed that the extrusion could destroy the original microcrystalline structure of corn starch with new starch-lipids.(4)There wasn't new characteristic absorption peaks on the FTIR.The results showed that extrusion didn't produce new chemical bonds and functional groups.3 The effects of the diameter of choke ring,the pitch of screw,the interval of spindle and the speed of screw on the syrup indicators of extruded corn were studied.Dextrose Equivalent of corn syrup,glucose syrup yield and filtration rate were increased firstly with the increase of the screw parameters and then decreased.The light of syrup chromaticity was decreased with the increase of the speed of screw and the diameter of choke ring.And it was decreased with the increase of the pitch of screw and the interval of spindle then increased.4 The screw parameters were taken as the influencing factors,syrup indicators were taken as response value and the method of quadratic orthogonal rotating combination design of four factors and five levels was used.The final optimization results were gotten by analyzing response surface:X₁:the diameter of choke ring was 90.0mm,X₂:the pitch of screw was 18.0mm,X₃:the interval of spindle was 17.5mm,X₄:the speed of screw was120.0r/min.