The impact of psyllium gelation behaviour on in vitro colonic fermentation properties

Psyllium is a viscous, gel forming fibre with properties that have led it to be used for alleviating gastrointestinal discomfort. We previously identified fractions of psyllium differing flow properties. Fraction 1 (F1) forms non-gelling solution containing rhamnose. galactose, and arabinose. 2 (F2) fluid-like mainly xylose arabinose, 3 (F3) has almost identical monosaccharide linkage composition F2, but an insoluble, self-supporting gel. performed in vitro batch fermentation experiments seeded human stool. Metabolomics were using 1H NMR, FISH calcofluor white direct red 23 visualise the gels after fractions. The total amount gas short chain fatty acid produced was significantly higher F1, compared F2 F3. F3 production lower than metabolite between did not differ. All preferentially lead propionate instead butyrate ratio 58:35:7, 54:38:8, 61:33:6 (acetate: propionate: butyrate) respectively. Microscopy showed differences how broke down demonstrated localisation bacteria on outer edge each fraction. These results suggest these structure key factor determines fermentability. Flow may play role production, suggesting directions future investigation. Isolated clinical benefit above unrefined powder aiding treatment