Effect of the Energy of Extrusion on the Starch Gelatinization

압출성형 에너지가 녹말의 호화에 미치는 영향

  • Chung, Moon-Young (Department of Food Science and Technology, Dongguk University) ;
  • Lee, Seung-Ju (Department of Food Science and Technology, Dongguk University)
  • Published : 1997.02.01

Abstract

The effect of the energy supplied in extrusion on the starch gelatinization was analyzed. The energy needed for extrusion is generated by motor and heater. The motor energy is transformed into a thermal energy by heat dissipation and a mechanical energy, and the heater energy is of a thermal energy. At the low barrel temperature $({\leq}80^{\circ}C)$, it was found out there are two kinds of thermal energy by heat dissipation: one by a powder friction of corn grit with low moisture contents and the other by a viscous dissipation of corn grit with high moisture contents. The dissipated thermal energy by the powder friction was more effective on the starch gelatinization than that by the viscous dissipation. The effect of the mechanical energy was also analyzed in terms of a relative mechanical energy. The gelatinization of corn grit with high moisture contents $({\geq}33%)$ largely depended on the change in the relative mechanical energy, whereas that with low moisture contents $({\leq}30%)$ hardly depended on it.

Keywords

extrusion;starch gelatinization;thermal energy;mechanical energy;heat dissipation