Crystalline Structure of the Extrudate of High Amylose Corn Starch

압출성형 고아밀로즈 옥수수전분의 결정 구조

  • Kim, Ji-Yong (Center for Advanced Food Science and Technology (CAFST) Graduate School of Biotechnology, Korea University) ;
  • Lee, Cherl-Ho (Center for Advanced Food Science and Technology (CAFST) Graduate School of Biotechnology, Korea University)
  • 김지용 (고려대학교 생명공학원 식품가공핵심기술연구센타) ;
  • 이철호 (고려대학교 생명공학원 식품가공핵심기술연구센타)
  • Published : 1998.10.01

Abstract

Crystalline structure of the extrudate of high amylose corn starch was studied by X-ray diffractometer and $^{13}C\;NMR$. The X-ray diffraction crystal ratio of the extrudates (barrel temperature $100^{\circ}C$ )of high amylose corn starch slightly increased from 6.08% to 8.37% by increasing feed moisture content from 25% to 45%. But extrudates of high amylose corn starch showed similar crystal ratio on various extrusion conditions. Extrudates of high amylose corn starch (feed moisture content 20%, barrel temp $140^{\circ}C$) showed more enlarged crystal structure than that of non-extrudates. The perpendicular distance of crystal increased by extrusion. Crystal ratio was changed from $6.3{\sim}8.3%$ to $4.5{\sim}5.8%$ during storage at $4^{\circ}C$. Starch configuration was examined with $^{13}C\;NMR$. Double helical content was measured by $^{13}C\;NMR$ method. The highest double helical content (60%) was obtained from high amylose corn starch extrudate (barrel temp.: $100^{\circ}C$, feed moisture content 45%). Double helical contents and resistant starch (RS) yield (pancreatin) were positively correlated. However, double helical content of the extrudates was not changed by the storage at $4^{\circ}C$.