The purpose of the study was to set up an in vitro model of the colon which
would permit the analysis of cellulose fermentation by human colonic microflora. Studies
of the degradation of polysaccharides by colonic bacteria may help to explain the observed
physiological consequences of consuming dietary fiber common in foods. This study
resulted in the use of a simple anaerobic batch fermentation system. It is assumed that the
bacteria in fresh feces are representative of colonic bacteria. This batch culture system
consists of the culture medium, the food fiber and the fecal inoculum. The fecal inoculum
is prepared from freshly voided feces from a single individual. The food fiber is prepared
from the vegetable/fruit starting material by repeated extraction with 90% ethanol,
resulting in an alcohol insoluble residue(AIR). Extents of cellulose fermentation were
measured after 4, 8, 12 and 24 hour fermentation periods at 37°C. The cellulose content of
the samples before and after fermentation was determined by measuring the glucose yield (glucose oxidase assay) from an acid hydrolysate of the residue remaining after repeated
acid detergent extractions. The extent of cellulose fermentation was then estimated by
difference. The susceptibility to intestinal fermentation of the cellulose component of
acorn squash and red beets was investigated using this model system. The cellulose content of squash and beet AIR was 26.71% ± 0.95% and 23.22% ± 0.89%, respectively.
The extent of cellulose of fermentation of squash cellulose after 4, 8, 12 and 24 hrs
incubation was 6.04% ± 0.69%, 10.58% ± 2.10%, 17.11% ± 6.37% and 96.18% ± 1.36%,
respectively. The extent of fermentation of beet cellulose after 4, 8, 12 and 24 hrs
incubation was 17.52% ± 1.83%, 23.52% ± 1.44%, 30.53% ± 4.12% and 96.06% ± 0.39%,
respectively. The results indicate that the cellulose component of both vegetables is
susceptible to considerable degradation within the human intestinal tract. / Graduation date: 1991
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27149 |
| Date | 10 April 1991 |
| Creators | Chang, Hung-pi |
| Contributors | Penner, Michael H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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