4 research outputs found
Degradation Of Dietary Fiber By Faecal Bacteria And Potential Physiological Effects
Dietary fiber was extracted from Nigerian ‘gari’, Ex
Mannihot esculenta ; plantain, Musa paradisiaca ; Gnetum africana
and Telfaria occidentalis and these fiber sources were referred to as
GAF, PLF, GF and TF, respectively. Mannihot esculenta and Musa
paradisiaca are rich sources of carbohydrate and the fiber extraction
was done using termamyl 120L and amyloglucosidase. Gnetum africana and
Telfaria occidentalis are vegetables and the acetone dried powder
method was employed for fiber extraction. The fiber extracted from each
source was subjected to degradation by the gut microbial flora and the
extent of degradation after 72 h was determined. Water holding capacity
(WHC) of each fiber was measured before and after the degradation. The
short chain fatty acids (SCFA) produced during degradation were
measured chromatographically. Exposure of the fibers to the gut
microflora showed that the non-vegetable fibers (GAF, PLF) were more
readily degraded than the vegetable fibers (GF and TF). Consequently,
the percentage of the undegraded fiber after 72 h of incubation was
highest with the vegetable fibers; GF, 80.0 % and TF, 83.3 %, while
that of the non-vegetable fibers (GAF and PLF) was 62.0 % and 72.5 %,
respectively. The degradation by the microflora affected the WHC of the
fibers (except TF). Water holding capacity (WHC) for GF was 11.1 ±
3.3 g H2O / g fiber, before degradation and 6.3 ± 2.5 g H2O / g
fiber after degradation, indicating a percent decrease of about 43.2%.
Similar decrease was observed for GAF (30.4 %) and PLF (13.9 %). Only
acetic and butyric acid were detected in the fermenting slurry. The
relative composition of acetic acid from each of the fiber source (GAF,
62.0 %; PLF, 70.4%; GF, 62.5%; TF, 52.9%) was found to be greater than
that from the slurry (control) (42%). The low pH created by the actions
of the microflora in the caecal lumen will decrease the toxicity of
luminal contents to the gut mucosa and protect against cancer of the
colo