In Vitro Fermentation Characteristics of Native Soluble Fiber Sources by Human Colonic Bacteria

Abstract

Fermentation of 20 soluble fibers (alginate [ALG], apple pectin [AP], arabinogalactan [AG], carrageenan [CG], carboxymethylcellulose [CMC], citrus pectin [CP], gellan gum [GLG], guar gum [GUG], gum Arabic [GA], gum ghatti [GGH], gum karaya [GK], hydrolyzed guar gum [HGG], konjac flour [KF], locust bean gum [LBG], methylcellulose [MC], oat‐β‐glucan [OBG], psyllium [PS], tomato pectin [TP], tragacanth gum [TG], and xanthan gum [XG]) was evaluated in vitro using three human fecal inocula. Serum bottles (n = 1,008; 125 mL each) were used in a completely randomized design experiment with treatments being arranged as a 20 (substrates) × 8 (incubation times; 1.5, 3, 4.5, 6, 9, 12, 18, and 24 h) factorial. At 24 h, in vitro dry matter disappearance varied (P < 0.05) as it was lowest (20.3%) for GK, moderate (40.1 to 70.6%) for AP, CP, GLG, GGH, and PS, and highest (≥ 91.0%) for the others. At 24 h, gas production also varied (P < 0.05) and was highest (≥ 74.0 mL) for GUG, HGG, KF, LBG, OBG, PS, TP, and TG. Of the remaining substrates, four (AP, AG, CG, and CP) had moderate amounts (30.5 to 58.7 mL), four (ALG, GA, GGH, and XG) had very small amounts (≤ 26 mL), and four (CMC, GLG, GK, and MC) had no gas produced. Several soluble fiber sources appear to have high potential in supporting human colon health. The concern with high gas production by some of these fiber sources, however, may limit their supplementation.