In Vitro Fermentabilities of Purified Fiber Supplements

ABSTRACT Six commonly used dietary fiber supplements (pectin, tragacanth gum, psyllium gum, guar gum, soy fiber and cellulose) were fermented in vitro with human fecal microbiota for 4, 8,12, and 24 hr. Short chain fatty acids (SCFA), hydrogen and methane productions, and neutral‐detergent fiber digestibility differed significantly with fiber source. The most rapid fermentation rate was with pectin followed by psyllium gum, tragacanth gum, guar gum, soy fiber, and finally cellulose. Such differences in fermentability should be considered when food products are formulated. Dietary fiber source and intake may also affect breath hydrogen measurements and estimates of available carbohydrate malabsorption.