In Vitro Bile Acid Binding of Flours from Oat Lines Varying in Percentage and Molecular Weight Distribution of β-Glucan

Sayar, Sedat; Jannink, Jean‐Luc; White, Pamela J.

doi:10.1021/jf051380g

Cited by 43 publications

(81 citation statements)

References 25 publications

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“…The authors concluded that other components of the oat fraction might also have contributed to the bile acid binding. This is supported by the study of Sayar et al [38] which described that partial lichenase hydrolysis did not affect bile acid binding of β-glucan-rich oat fractions using an in vitro centrifugation method. These results support our hypothesis that centrifugation-based methods do not reflect the impact of viscosity on the reabsorption of bile acids.…”

Section: Discussionsupporting

confidence: 66%

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis

Naumann

Schweiggert‐Weisz

Bader-Mittermaier

et al. 2018

IJMS

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To explain the cholesterol-reducing effects of dietary fibres, one of the major mechanisms proposed is the reduced reabsorption of bile acids in the ileum. The interaction of dietary fibres with bile acids is associated with their viscous or adsorptive effects. Since these fibre characteristics are difficult to investigate in vivo, suitable in vitro methodologies can contribute to understanding the mechanistic principles. We compared the commonly used centrifugal approach with a modified dialysis method using dietary fibre-rich materials from different sources (i.e., barley, citrus, lupin, and potato). Digestion was simulated in vitro with oral, gastric, and small intestinal digestion environments. The chyme was dialysed and released bile acids were analysed by high-performance liquid chromatography. The centrifugation method showed adsorptive effects only for cholestyramine (reference material) and a high-fibre barley product (1.4 µmol taurocholic acid/100 mg dry matter). Alternatively, the dialysis approach showed higher values of bile acid adsorption (2.3 µmol taurocholic acid/100 mg dry matter) for the high-fibre barley product. This indicated an underestimated adsorption when using the centrifugation method. The results also confirmed that the dialysis method can be used to understand the influence of viscosity on bile acid release. This may be due to entrapment of bile acids in the viscous chyme matrix. Further studies on fibre structure and mechanisms responsible for viscous effects are required to understand the formation of entangled networks responsible for the entrapment of the bile acids.

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Section: Discussionsupporting

confidence: 66%

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis

Naumann

Schweiggert‐Weisz

Bader-Mittermaier

et al. 2018

IJMS

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“…The low MW and medium MW β-glucan bound more bile acid than did the high MW β-glucan. The bile-acid binding values of the oat flours from different oat lines and oat bran were in the range of 6% to13.5% (4,19).…”

Section: Resultsmentioning

confidence: 99%

In Vitro Bile-Acid Binding and Fermentation of High, Medium, and Low Molecular Weight β-Glucan

Kim

White

2009

J. Agric. Food Chem.

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The impact of beta-glucan molecular weight (MW) on in vitro bile-acid binding and in vitro fermentation with human fecal flora was evaluated. beta-Glucan extracted from oat line 'N979-5-4' was treated with lichenase (1,3-1,4-beta-D-glucanase) to yield high (6.87x10(5) g/mol), medium (3.71x10(5) g/mol), and low (1.56x10(5) g/mol) MW fractions. The low MW beta-glucan bound more bile acid than did the high MW beta-glucan (p<0.05). If the positive control, cholestyramine, was considered to bind bile acid at 100%, the relative bile-acid binding of the original oat flour and the extracted beta-glucan with high, medium, and low MW was 15, 27, 24, and 21%, respectively. Significant effects of high, medium, and low MW beta-glucans on total SCFA were observed compared to the blank without substrate (p<0.05). There were no differences in pH changes and total gas production among high, medium, and low MW beta-glucans, and lactulose. The low MW beta-glucan produced greater amounts of SCFA than the high MW after 24 h of fermentation. Among the major SCFA, more propionate was produced from all MW fractions of extracted beta-glucans than from lactulose. In vitro fermentation of extracted beta-glucan fractions with different MW lowered pH and produced SCFA, providing potential biological function.

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“…The human digestive process of inulin was simulated in vitro by using the method described in Sayar et al, 2005 [31]. Inulin Frutafit IQ solution (150 mg/mL) was subjected to a cooking step in boiling water for 4 minutes.…”

Section: Methodsmentioning

confidence: 99%

Antioxidant Activity of Inulin and Its Role in the Prevention of Human Colonic Muscle Cell Impairment Induced by Lipopolysaccharide Mucosal Exposure

et al. 2014

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BackgroundFructans, such as inulin, are dietary fibers which stimulate gastro-intestinal (GI) function acting as prebiotics. Lipopolysaccharide (LPS) impairs GI motility, through production of reactive oxygen species. The antioxidant activity of various fructans was tested and the protective effect of inulin on colonic smooth muscle cell (SMC) impairment, induced by exposure of human mucosa to LPS, was assessed in an ex vivo experimental model.MethodsThe antioxidant capacity of fructans was measured in an in vitro system that simulates cooking and digestion processes. Human colonic mucosa and submucosa, obtained from disease-free margins of resected segments for cancer, were sealed between two chambers, with the mucosal side facing upwards with Krebs solution with or without purified LPS from a pathogenic strain of Escherichia coli (O111:B4) and inulin (Frutafit IQ), and the submucosal side facing downwards into Krebs solution. The solutions on the submucosal side were collected following mucosal exposure to Krebs in the absence (N-undernatant) or presence of LPS (LPS-undernatant) or LPS+inulin (LPS+INU-undernatant). Undernatants were tested for their antioxidant activity and the effects on SMCs contractility. Inulin protective effects on mucosa and submucosa layers were assessed measuring the protein oxidation level in the experimental conditions analyzed.ResultsAntioxidant activity of inulin, which was significantly higher compared to simple sugars, remained unaltered despite cooking and digestion processes. Inulin protected the mucosal and submucosal layers against protein oxidation. Following exposure to LPS-undernatant, a significant decrease in maximal acetylcholine (Ach)-induced contraction was observed when compared to the contraction induced in cells incubated with the N-undernatant (4±1% vs 25±5% respectively, P<0.005) and this effect was completely prevented by pre-incubation of LPS with Inulin (35±5%).ConclusionsInulin protects the human colon mucosa from LPS-induced damage and this effect appears to be related to the protective effect of inulin against LPS-induced oxidative stress.

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In Vitro Bile Acid Binding of Flours from Oat Lines Varying in Percentage and Molecular Weight Distribution of β-Glucan

Cited by 43 publications

References 25 publications

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis

In Vitro Bile-Acid Binding and Fermentation of High, Medium, and Low Molecular Weight β-Glucan

Antioxidant Activity of Inulin and Its Role in the Prevention of Human Colonic Muscle Cell Impairment Induced by Lipopolysaccharide Mucosal Exposure

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