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In Vitro Fermentation of High‐Amylose Cornstarch by a Mixed Population of Colonic Bacteria
Author(s) -
Christl Stefan U.,
Katzenmaier Uta,
Hylla Silke,
Kasper Heinrich,
Scheppach Wolfgang
Publication year - 1997
Publication title -
journal of parenteral and enteral nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.935
H-Index - 98
eISSN - 1941-2444
pISSN - 0148-6071
DOI - 10.1177/0148607197021005290
Subject(s) - starch , fermentation , resistant starch , food science , butyrate , chemistry , feces , population , amylose , biochemistry , biology , microbiology and biotechnology , medicine , environmental health
Background: Malabsorbed starch is probably the most important substrate for bacterial fermentation in the human large intestine. Fermentability of starch may depend on the composition of the colonic flora and its adaptation to the substrate supply. Methods: Ten healthy volunteers were fed a controlled diet containing either 7.0 to 8.3 or 50.7 to 59.7 g/d of resistant starch (Hylon VII) for 4 weeks. At the end of each diet period, fecal starch concentrations were measured. Fecal samples were incubated in 48‐hour batch cultures containing 10 g/L Hylon VII or digestible Lintner's starch. Bacterial breakdown of starch and short‐chain fatty acid concentrations were measured at 0, 3, 6, 12, 24, and 48 hours. Results: Fecal starch concentrations were higher during the Hylon VII period (35.7 ± 16 vs 8.9 ± 3.3 mg/g). Starch was fermented rapidly and completely in vitro in all but two subjects. Fermentability of resistant starch was comparable to that of digestible starch. No differences were found between the dietary periods. Fermentation of resistant starch produced higher rates of n ‐butyrate. Two subjects had substantially higher fecal starch concentrations. In vitro starch breakdown in these subjects was slow and incomplete. Conclusions: Fermentation of resistant starch by the colonic microflora was rapid and complete in 8 of 10 subjects. No adaptation of the fermentation capacity was observed after 4 weeks of dietary resistant starch supplementation. Fermentation of resistant starch increased the proportion of n‐butyrate in vitro. In two subjects, fecal starch concentrations were substantially higher than in the other subjects and in vitro starch fermentation was slow and incomplete. (journal of Parenteral and Enteral Nutrition 21:290–295, 1997)