| This experiment was conducted to study the effect of tempering temperature and extrusiontemperature on the quality of extruded corn and arabinoxylan degradation, it also studied the factorsthat affect the bulk density of extruded corn. Conclusions are drawn as follows:(1) An experiment was conducted to study the effects of quenching and tempering temperature andextrusion temperature on the quality of extruded corn. The results showed that, quenching andtempering temperature was linear positive correlation with starch gelatinization degree and negativelinear correlation with arabinoxylan; Extrusion temperature was linear positive correlation with starchgelatinization degree, and negative linear correlation with arabinoxylan; High temperature tempering-low temperature extrusion helps to improve maize starch gelatinization degree, with low damagementfor the solubility of starch and protein.(2) An experiment was conducted to study the influence factors and its influence on extruded corndensity. The results showed that, keep constant moisture content and starch gelatinization degree,granularity is positively correlated with the bulk density; keep constant granularity and starchgelatinization degree, moisture content is positively correlated with the bulk density; keep constantmoisture content and granularity, starch gelatinization degree is positively correlated with the bulkdensity.(3) An experiment was conducted to study the puffing characteristics of different maize types. Theresults showed that, there was no significant difference in indexes among the three kinds of cornmaterials and extruded corn, it may be related to raw material sampling error and testing condition.The overall conclusion: It is suggested to use high temperature tempering-low temperature extrusionduring the proccesing. Starch gelatinization degree and protein solubility are the quality evaluationindex of extruded corn. There is a linear relationship between the bulk density and moisture content,particle size and starch gelatinization degree of extruded corn. With the same particle size and moisturecontent, bulk density is available to evaluate the extruded corn fastly; It is suggested to use hightemperature tempering-low temperature extrusion during the proccesing. When samples were crushedby the same mesh (1.0~1.2mm), and drying to the same moisture content, bulk density is suitable forfast evaluation of the quality of extruded corn. |
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