Chemistry Reference
In-Depth Information
Inulin is reported to be more slowly fermented than oligofructose (Roberfroid,
2005b). It was recently confirmed that scFOS is also more rapidly fermented than
inulin. Using
in vitro
batch fermentation and human fecal inoculum, Stewart et al.
(2008) compared the fermentation profile of scFOS, two types of oligofructose and
three types of inulin. After a 4-hour fermentation period, total SCFA concentration
was higher for scFOS than for the three inulins tested, nonsignificant for two, signifi-
cant for one. This trend continued across the first 12 hours of the incubation. Further,
the rate of SCFA production was higher for scFOS than for inulin, particularly in the
first 4-hour period,
p
< 0.05. Differences in concentration and rate were largely due
to acetate production which is not surprising as scFOS is generally more bifidogenic
than inulin and bifidobacteria produce acetate.
In addition to SCFA production, fructans also differ in gas production, with scFOS
producing less gas than other fructans. Probert and Gibson (2002) used an
in vitro
fermentation system with human fecal flora inoculum to compare gas production by
four fructans: scFOS, oligofructose, branched FOS, and levan. scFOS produced sig-
nificantly less gas than oligofructose within the first 4 hours (
p
= 0.01), less gas than
oligofructose and branched FOS within 8 hours (
p
= 0.01,
p
= 0.05, respectively),
and by 24 hours scFOS produced less gas than all other fructans tested (
p
= 0.01). As
gas/flatus is typically the highest reported symptom of gastrointestinal (GI) distress
following fructan consumption (Bouhnik et al., 1999, 2004, 2006) and is typically
experienced by more people than for other symptoms of GI distress (Bouhnik et al.
1999, 2006), differences in gas production between fructans should be considered
when selecting ingredients to formulate consumer-accepted food products.
Several authors have tested GI tolerance to scFOS and other fructans. Where
tolerance to different fructans was compared within the same study, differences
between different types of fructans emerged. Bouhnik et al. (2004) tested the GI
tolerance of 10 g of seven different nondigestible carbohydrates for 7 days, two of
which included scFOS and inulin. When scFOS was consumed, changes in GI dis-
tress symptoms were similar to or lower than the control with the exception of bloat-
ing (Table 2.9). scFOS was better tolerated than inulin, with a 12-fold lower effect on
flatus and 6-fold lower effect on bloating. On average, subjects reported no change
in abdominal pain with scFOS, but this was increased with inulin. Therefore, 10 g/
day of scFOS was well tolerated with little effect compared with the control, and
less GI distress compared with inulin. Bouhnik et al. (1999, 2006) also showed that
that scFOS is well tolerated up to 10 g/day in two dose-response studies. In the
1999 study, they assessed doses of 0, 2.5, 5, 10, 20 g/day scFOS over 7 days. With
respect to flatus, the 2.5, 5.0, and 10 g/day scFOS doses were well tolerated, with no
significant difference between the doses. However, the flatus observed with the 20 g/
day dose was significantly higher,
p
< 0.05. No significant differences were reported
amongst the 0 to 20 g/day doses for bloating, borborygmi, or abdominal pain. In the
2006 study, doses of 0, 2.5, 5, 7.5, and 10 g/day scFOS were consumed for 7 days.
Flatus, borborygmi, and abdominal pain did not differ between the doses. However,
some bloating was observed at the lower doses.
