Effects Of Particle Size And Gelatinization On The Physicochemical Properties Of Corn Dough

In order to explore the changing relationship between the particle size and their physicaland chemical parameters, this paper selects grits as raw material, and they were crushed atdifferent time to get different particle size of corn flour; In addition, at the aim of obtainingthe most optimal pasting combination and adding amount,gelatinized corn flour is preparedthrough the twin-screw extruder, then mix the gelatinized corn flour with corn flour accordingto a certain proportion to analyze the effect of gelatinization degree on TPA parameters ofcorn dough；Comparing the TPA parameters with different blending proportion of mixedpowder-wheat flour, raw powder-wheat flour, and wheat flour dough as reference substance,and measure the corresponding product (noodles) properties. The results are shown asfollows;1.Analyzed the angle of repose, water retention, water absorption index and watersoluble index indicators of different particle size corn flour, the results show that with thereduction of corn flour volume average particle size, the content of amylase decreasesslightly at first and then level off. The angle of repose, water retention, water soluble index,water absorption index and damaged starch content all demonstrate an increasing trend. Withthe decreasing of corn flour particle size, its thermal stability and aging degree falls, while theparticle size of starch gelatinization degree increase; SDS-PAGE results show that thecrushing time and particle size have no obvious effect on the protein primary structure and theprotein content, that is to say, crushing process has no obvious effect on protein degradation.2.In the experiment of exploring the particle size and adding water amount, the TPAparameters of dough suggest that under the condition of the same adding water, the hardness,adhesion and cohesion of corn dough increase with the decreasing of the particle size; Underthe same conditions of the particle size, with the increasing of adding water, the hardness ofcorn dough show a declining trend, while corn dough cohesion show a rising trend,adhesion does not present a regular change. Then choose10min group and70%adding wateras optimum condition of making dough. Under the condition of adding no water extrusionafter puffing powder as pasting in the mixed dough, the gelatinization degree is of 94.51%.After adding gelatinized corn flour, dough TPA parameters show that as thegelatinization degree insurrection, the dough rises in hardness, while its adhesion andcohesion are declining, but cohesion value does not change much. Compared with wheatdough quality and structure parameters as well as practical and operability, gelatinizationdegree of70%of the proportion is chosen as the blending composition ratio in mixedpowder-wheat flour dough.3.TPA parameters of mixed dough show that under the condition of same blending ratio,the hardness and adhesive property of mixed powder-wheat dough are significantly higherthan that of raw powder-wheat flour dough, and there is no significant difference in cohesionproperty. Finally，chose the ratio of corn flour to wheat flour is of6:4as the compositionratio,which is used in both two kinds of mixed dough in practical application test.4.After cooked，there is a great difference among hardness，work of shear，resistances toextension，extensibility，extension ratio，stickiness and adhesion of three kinds of noodle.Additionally，cooked noodle is greater than that of raw one. From the results of sensoryevaluation，mixed powder-wheat noodle gets the highest sensory score，which is far morehigher than that of normal powder-wheat and wheat noodle.