Gastrointestinal conditions influence the solution behaviour of cereal β-glucans in vitro

• Published in: Food chemistry Vol. 130; no. 3; pp. 536 - 540
• Main Authors: Ulmius, Matilda, Adapa, Srimannarayana, Önning, Gunilla, Nilsson, Lars
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2012; Elsevier
• Subjects: Annan teknik; barley; beta-glucans; Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Biologi; Biological and medical sciences; Biological Sciences; Calcofluor; Cereal and baking product industries; Cereal b-glucan; Cereal β-glucan; digestion; Engineering and Technology; Field-flow fractionation; Food Engineering; Food industries; fractionation; Fundamental and applied biological sciences. Psychology; Gastrointestinal model; Livsmedelsteknik; molecular weight; Natural Sciences; Naturvetenskap; Oat bran; oats; Other Engineering and Technologies; prediction; small intestine; soluble fiber; Teknik; Calcofluor; Field-flow fractionation; Cereal β-glucan; Gastrointestinal model; Oat bran; Cereal bran; Field flow fractionation; Oat; Digestive system; Gastrointestinal; In vitro; Glucan; Cereal product; Cereal; Models; Polysaccharide; Solution
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2011.07.066

► We studied the β-glucan solution behaviour along an in vitro gastrointestinal tract. ► Calcofluor labelling coupled to field-flow fractionation was successfully monitored. ► β-Glucan aggregates are disrupted in gastric pH but re-form in small intestinal pH. ► The aggregation of pure β-glucans in intestinal conditions reflects the onset of gel formation which may add to health effects. ► It is difficult to predict β-glucan intestinal activity by analysing food products. The solution behaviour of β-glucans in a gastrointestinal model was investigated in order to explore the mechanisms explaining the physiological effects of the soluble fibre. Asymmetrical flow field-flow fractionation was used to determine the molar mass distribution, and in-line calcofluor labelling allowed specific detection of β-glucans in complex samples. When dispersed in water, weight-average molar mass (Mw) was determined to 1×106g/mol for pure oat and barley β-glucans, and 200×106g/mol for β-glucans in oat bran, indicating that the β-glucans were aggregating. Samples from the gastric digestion displayed disrupted aggregates, while samples from the small intestinal digestion contained re-formed aggregates. Additionally, the aggregates from pure β-glucans were considerably denser after intestinal digestion. This may be construed as gel-formation in the small intestine, which should be tested for its relevance to health effects. Our results signal the difficulties in predicting β-glucan activity in the gastrointestinal tract purely from analysis of the fibre-rich product.