title: Structural features of soluble cereal arabinoxylan fibers associated with a slow rate of in vitro fermentation by human fecal microbiota.
abstract: Most soluble dietary fibers ferment rapidly in the proximal colon, potentially causing discomfort and poor tolerability. Alkali-extracted arabinoxylan isolates from corn, wheat, rice and sorghum brans were prepared, through hydrolysis (except sorghum) and ethanol fractionation, to have a broad range of initial fermentation rates, and their linkage patterns were determined to understand structural aspects related to slow fermentation rate. They were all highly branched polymers with degree of substitution greater than 64%. There was no relationship of molecular mass, arabinose:xylose ratio, or degree of substitution to fermentation rate patterns. Slow fermenting wheat and corn arabinoxylans had much higher amount of terminal xylose in branches than fast fermenting rice and sorghum arabinoxylans. The slowest fermenting wheat arabinoxylan additionally contained a complex trisaccharide side chain with two arabinoses linked at the O-2 and O-3 positions of an arabinose that is O-2 linked to the xylan backbone. Structural features were proposed for tolerable slowly fermentable arabinoxylan with possible beneficial fermentation function into the distal colon.
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address: fagiptr@ku.ac.th.
authors.forename: Pinthip
authors.initials: P
authors.lastname: Rumpagaporn
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address: breuhs@purdue.edu.
authors.forename: Brad L
authors.initials: BL
authors.lastname: Reuhs
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address: amandeep.kaur.ctr@usuhs.edu.
authors.forename: Amandeep
authors.initials: A
authors.lastname: Kaur
authors.affiliation: Department of Animal Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address: jpatters@purdue.edu.
authors.forename: John A
authors.initials: JA
authors.lastname: Patterson
authors.affiliation: Division of Digestive Diseases and Nutrition, Rush University, Chicago, IL 60612, USA. Electronic address: Ali_Keshavarzian@rush.edu.
authors.forename: Ali
authors.initials: A
authors.lastname: Keshavarzian
authors.affiliation: Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address: hamakerb@purdue.edu.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Hamaker
mesh_terms: D004043:Dietary Fiber / Q000032:analysis*; D005243:Feces / Q000737:chemistry* / Q000382:microbiology*; D005285:Fermentation; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D064307:Microbiota; D012275:Oryza / Q000737:chemistry; D014908:Triticum / Q000737:chemistry; D014990:Xylans / Q000737:chemistry*; D003313:Zea mays / Q000737:chemistry
chemical_list: D004043:Dietary Fiber; D014990:Xylans; C085118:arabinoxylan
keywords: Arabinoxylan; Dietary fiber; Fermentation; Structure; Sugar linkages; Tolerability