Extrusion induced low-order starch matrices: enzymic hydrolysis and structure

Bin Zhang, Sushil Dhital, Bernadine M. Flanagan, Paul Luckman, Peter J. Halley, Michael J. Gidley

Research output: Contribution to journalArticleResearchpeer-review

55 Citations (Scopus)


Waxy, normal and highwaymen maize starches were extruded with water as sole plasticizer to achieve low-order starch matrices. Of the three starches, we found that only high-amylose extrudate showed lower digestion rate/extent than starches cooked in excess water. The ordered structure of high-amylose starches in cooked and extruded forms was similar, as judged by NMR, XRD and DSC techniques, but enzyme resistance was much greater for extruded forms. Size exclusion chromatography suggested that longer chains were involved in enzyme resistance. We propose that the local molecular density of packing of amylose chains can control the digestion kinetics rather than just crystallinity, with the principle being that density sufficient to either prevent/limit binding and/or slow down catalysis can be achieved by dense amorphous packing.

Original languageEnglish
Article number10197
Pages (from-to)485-496
Number of pages12
JournalCarbohydrate Polymers
Publication statusPublished - 10 Dec 2015
Externally publishedYes


  • Enzyme-resistant starch
  • Extrusion
  • High-amylose starch
  • In vitro digestion
  • Local molecular density

Cite this