Changes in dietary fiber fractions and gut microbial fermentation properties of wheat bran after extrusion and bread making

Jennifer A. Arcila, Steven A. Weier, Devin J. Rose

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

The dietary fiber in wheat bran, principally non-starch polysaccharides (NSP), is mostly water-unextractable and is poorly utilized by human gut microbiota. The purpose of this study was to determine the change in water-extractability of NSP in wheat bran upon extrusion and then to determine if extrusion impacts the availability of NSP for fermentation by the fecal microbiota during in vitro fecal fermentation. A secondary objective was to incorporate extruded bran into a product formulation to determine if changes in WE-NSP and NSP fermentation were maintained in a finished product. Bran was extruded using combinations of high or low moisture (15% and 30% wb) and high or low screw speed (120 and 250. rpm). All extrusion conditions resulted in increases in WE-NSP and fecal microbiota short chain fatty acid (SCFA) production upon fermentation compared with unextruded bran. Low screw speed and low moisture resulted in the greatest increase in WE-NSP (3-fold) as well as the highest production of SCFA during fermentation (1.4-fold) compared with unextruded bran. Whole wheat breads containing extruded bran did not show increases in either WE-NSP or SCFA production compared with the control. In conclusion, extrusion of wheat bran increased WE-NSP, which enabled greater fermentability by human fecal microbiota. However, once extruded bran was used in a whole wheat bread formulation the changes in fermentation outcomes were no longer evident.

Original languageEnglish (US)
Pages (from-to)217-223
Number of pages7
JournalFood Research International
Volume74
DOIs
StatePublished - Aug 1 2015

Keywords

  • Arabinoxylans
  • Butyrate
  • Moisture
  • Non-starch polysaccharides
  • Screw speed
  • Short chain fatty acids

ASJC Scopus subject areas

  • Food Science

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