2.4.3. In vitro fermentation
In vitro batch fermentation was conducted according to the
method of Lebet, Arrigoni, and Amadò (1998), with a few modifications.
Fermentation was performed in triplicate for each noodle
sample. One hundred mg of pre-digested noodles was added to 8 ml of fermentation medium in a 20 ml serum bottle. The bottle
was sealed with a butyl rubber stopper and aluminum cap and
the headspace was flushed with N2 for 3 min to maintain anaerobic
conditions. The sample was then hydrated overnight at 4 C. After
equilibrating in a water bath at 37 C for 1 h, 2 ml of inoculum was
added to each bottle and the headspace was flushed again with N2
for 1 min. The bottles were incubated in a shaking water bath (50
strokes/min) at 37 C. Samples of the fermented broth (0.5 ml)
were taken at 24, 36 and 72 h and immediately placed in a freezer
at 20 C to stop fermentation. A control containing no sample was
used as a blank; inulin, which is a completely fermentable substrate,
was used as a reference.