The comparison of RS content in wholemeal wheat, rye and
wheat and oat blend breads (including literature references for
comparison) is presented in Table 4. The amount of RS formation
in sour dough fermented rye bread ranged from 3.91% to 2.86%.
This was higher than the amount recovered in bulk fermented
wheat bread which was only 1.23% at the lowest and 2.06% at
the highest. In the wheat and oat blend varieties, the maximum
quantity of RS recovered was 2.21% and the minimum was 1.47%.
The effect of various processing stages of 100% wheat and 70%
wheat 30% oat blend bread including processing stages of rye bread
making process on pH and TTA are presented in Fig. 2. The pH of
bulk fermented wheat dough, as well as that prepared from the
wheat and oat blend, decreased from around 6.5 following mixing,
to 5.3 after fermentation. There was no significant change in pH
after final proofing in both samples. The pattern of pH changes in
rye sourdough fermentation was different from that in the bulk
fermentation of the wheat and wheat and oat blend flours. After
inoculation and a 24 h fermentation period at various temperatures
(23, 30 and 37 C) the pH of rye sourdough dropped from
6.53 to as low as 3.95.