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The effect of in vitro gastrointestinal conditions on the structure and conformation of oat β-glucan

Korompokis, Konstantinos; Nilsson, Lars LU and Zielke, Claudia LU (2018) In Food Hydrocolloids 77. p.659-668
Abstract

A plethora of studies have shown that the physicochemical properties of oat β-glucan determine its health benefits. However, the impact of the passage through the gastrointestinal tract on the conformational and structural characteristics is not fully understood. The present study aims to elucidate the structure and conformation of gently extracted oat β-glucan before and after in vitro gastric and gastrointestinal digestion utilizing asymmetric flow field-flow fractionation (AF4) and NMR spectroscopy. The structural features and the bile acid-binding capacity of oat β-glucan were probed with NMR. Oat β-glucan without digestion presented primary aggregates with fringed micelle structure, and other high molar mass supramolecular... (More)

A plethora of studies have shown that the physicochemical properties of oat β-glucan determine its health benefits. However, the impact of the passage through the gastrointestinal tract on the conformational and structural characteristics is not fully understood. The present study aims to elucidate the structure and conformation of gently extracted oat β-glucan before and after in vitro gastric and gastrointestinal digestion utilizing asymmetric flow field-flow fractionation (AF4) and NMR spectroscopy. The structural features and the bile acid-binding capacity of oat β-glucan were probed with NMR. Oat β-glucan without digestion presented primary aggregates with fringed micelle structure, and other high molar mass supramolecular secondary aggregates were detected. Under gastric conditions, the molar mass was reduced and an increase in apparent density, suggesting more compact and disrupted aggregates, was observed. In the intestinal phase, the conformation was restored as prior digestion. No effect of the digestive enzymes on the conformation of oat β-glucan was shown, except from a modest effect of pepsin under gastric conditions. In contrast, the bile acids induced alterations to the apparent density of the oat β-glucan aggregates indicating a molecular interaction which was further confirmed with NMR by observing numerous changes in the resonance of bile acids' carbons in presence of oat β-glucan. In conclusion, the examination of oat β-glucan under in vitro gastrointestinal conditions with AF4 and NMR sheds light on the aggregation behavior and interaction mechanisms and enables a rich gain of knowledge for its physiological effects.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Aggregation, Asymmetric flow field-flow fractionation, Bile acids, In vitro digestion, NMR, Oat β-glucan
in
Food Hydrocolloids
volume
77
pages
659 - 668
publisher
Elsevier
external identifiers
  • scopus:85034614953
ISSN
0268-005X
DOI
10.1016/j.foodhyd.2017.11.007
language
English
LU publication?
yes
id
fb76340e-5768-4989-8c20-3ad5b72c0e89
date added to LUP
2017-12-11 11:19:11
date last changed
2018-10-07 05:02:44
@article{fb76340e-5768-4989-8c20-3ad5b72c0e89,
  abstract     = {<p>A plethora of studies have shown that the physicochemical properties of oat β-glucan determine its health benefits. However, the impact of the passage through the gastrointestinal tract on the conformational and structural characteristics is not fully understood. The present study aims to elucidate the structure and conformation of gently extracted oat β-glucan before and after in vitro gastric and gastrointestinal digestion utilizing asymmetric flow field-flow fractionation (AF4) and NMR spectroscopy. The structural features and the bile acid-binding capacity of oat β-glucan were probed with NMR. Oat β-glucan without digestion presented primary aggregates with fringed micelle structure, and other high molar mass supramolecular secondary aggregates were detected. Under gastric conditions, the molar mass was reduced and an increase in apparent density, suggesting more compact and disrupted aggregates, was observed. In the intestinal phase, the conformation was restored as prior digestion. No effect of the digestive enzymes on the conformation of oat β-glucan was shown, except from a modest effect of pepsin under gastric conditions. In contrast, the bile acids induced alterations to the apparent density of the oat β-glucan aggregates indicating a molecular interaction which was further confirmed with NMR by observing numerous changes in the resonance of bile acids' carbons in presence of oat β-glucan. In conclusion, the examination of oat β-glucan under in vitro gastrointestinal conditions with AF4 and NMR sheds light on the aggregation behavior and interaction mechanisms and enables a rich gain of knowledge for its physiological effects.</p>},
  author       = {Korompokis, Konstantinos and Nilsson, Lars and Zielke, Claudia},
  issn         = {0268-005X},
  keyword      = {Aggregation,Asymmetric flow field-flow fractionation,Bile acids,In vitro digestion,NMR,Oat β-glucan},
  language     = {eng},
  pages        = {659--668},
  publisher    = {Elsevier},
  series       = {Food Hydrocolloids},
  title        = {The effect of in vitro gastrointestinal conditions on the structure and conformation of oat β-glucan},
  url          = {http://dx.doi.org/10.1016/j.foodhyd.2017.11.007},
  volume       = {77},
  year         = {2018},
}