Research on granule structures and thermal properties of degerminated corn and extruded degerminated corn with enzyme and without enzyme

The granule structures and thermal properties of degerminated corn, extruded degerminated corn and enzymatically extruded degerminated corn were evaluated by methods of scanning election microscopy, X-ray irradiation, differential scanning calorimetry.The surface of degerminated corn without extrusion was smooth and complete, the surface of extruded degerminated corn and enzymatically extruded degerminated corn was broken. The crystalinity of degerminated corn, extruded degerminated corn and enzymatically extruded degerminated corn were 5.84, 5.63 and 7.40. The beginning of pasting temperature of three materials were 46.97, 43.11, 48.18 ℃, the peaking of pasting temperature of three materials were 98.63, 93.61, 98.25 ℃, respectively, the end pasting temperature of three materials were 196.79, 185.20, 188.54 ℃. The enthalpy change of three materials were 325.40, 271.30, 284.80 J/g, respectively.The pasting of three materials were 0.16, 0.87, 0.61.The results showed that extrusion can destroy integrity and crystal structure of degerminated corn, the crystalinity and enthaply change was decreased, the pasting was increased after extrusion. The enthaphy change of enzymatically extruded degerminated corn was higher than extruded degerminated corn, while the pasting was lower.