IN-VITRO METHOD FOR QUANTIFICATION OF THE FERMENTATION OF STARCH BY HUMAN FECAL BACTERIA

The major actions of undigested carbohydrates, such as non-starch poly saccharides and resistant starch, on the physiology of man are related to colonic fermentation. It is very difficult to study fermentation i n vivo. In vitro models are often used but these models differ in almo st every aspect even when only the simplest batch cultures of human fa eces are considered. Factors such as composition of the medium, buffer ing capacity, inoculum concentration, and fermentation time vary consi derably making direct comparison of the results from different studies impossible. The authors have devised a standard in vitro fermentation method for resistant starch and tested it in eight laboratories with a total of 40 individual faecal inocula. This simple method was well r eceived and taking biological variation into account yielded comparabl e results for 24 h short chain fatty acid production and residual star ch in all but one laboratory.