Figs. 7 and 8 show slices of MS and W breads, respectively. W
bread without fibre exhibited a coarser crumb grain than MS
sample (Figs. 7A and 8A). This result is consistent with the strength
of the two flours. A higher degree of gas cell coalescence had
a slight decrease in size of gas cells was observed at 7.5% (Fig. 7).
Inulin ST addition to MS flour gave finer crumb texture (smaller gas
cells) than the reference and HP samples (Fig. 7). This result might
be explained by gelatinisation delay due to inulin ST addition. The
consequence of this delay would be faster bubble inflation, which
gives greater strain hardening and higher proportion of finer cells
(Dobraszczyk and Roberts, 1994). Contrary to this, Rouille´ et al.
(2005) observed that low molecular weight sugars led to a decrease
in crumb fineness. This different behaviour could be due mainly to
preparation of doughs at constant hydration, which influences
dough consistency and starch gelatinisation.
ForWbread (Fig. 8), inulin ST addition at 2.5% and 5% gave finer
crumb texture than the reference, while a higher proportion of
coarse cells were observed at 7.5% content, confirming low bubble
stability, which induced failure and loss of gas retention during
higher expansion in the oven (Table 3). When inulin HP was added
to weak flour at 7.5%, a dense crumb was observed suggesting
excessive limitation of bubble growth during processing (Fig. 8D).