As mentioned above, the composition of raw materials for making particular type of
bread leavened using natural rye sourdough may slightly differ among bakeries. The weight
ratios of wheat and rye flours in traditional Czech soft fermented bread recipes are typically
around 1 : 1, the actual value often reflects the availability of particular commodity at the
market (and its cost as well). Nevertheless the ratio should not exceed 2 : 3 to ensure optimal
fermentation without yeast addition. To enable the use of even higher ratios of rye/wheat
flour and assess the impact of this raw material on the extent of acrylamide formation in
bread, dry rye sourdough had to be used. The initiation of leavening was achieved by bakery
yeasts addition. The acrylamide content in wheat rye breads ranged from 30 to 47 μg.kg-1 of
bread loaf. As shown in Fig. 4, no relationship between the portion of rye flour in dough and
the final acrylamide content in bread was found.