Biomedical Engineering Reference
In-Depth Information
8.7
Alternative Fermentations and Synergistic Affects
of Sourdough and Dough Additives
The nutritional importance of dietary fiber has been demonstrated in many studies.
Acceptable loaf volume with high-fiber, whole-grain bread is difficult to obtain. The
fermentation of bran allows enhanced water absorption and textural modification of
bran particles. The use of fermented bran in combination with an enzyme mixture
(a-amylases, xylanase and lipase) improved the volume, texture, and shelf life of
high- fi ber wheat bread [
58
]. Combined use of exogenous enzymes and sourdough
in wheat baking also enhanced the rate of acidification, improved bread volume,
and retarded staling [
13,
59,
60
]. Recently, sourdough in combination with cryopro-
tectants and/or conventional additives (e.g., honey, hydrocolloids) in frozen dough
technology were used to overcome problems such as prolonged final leavening
time, lower loaf volume, and poor bread characteristics [
61
] .
8.8
Conclusion
The addition of sourdough improves the quality of bread and has a long tradition in
production of wheat and rye bread. Organic acid, EPS, enzymes, and CO
2
synthesized
during sourdough fermentation by LAB and yeast are responsible for the positive
changes in dough and bread quality. Organic acids positively influence structure-
forming compounds of wheat and rye dough, particularly gluten, starch, and arabi-
noxylans. Furthermore, the production of organic acids and consequently the drop in
pH induces/inhibits endogenous enzymes like proteinases, pentosanases, and amy-
lases, also interfering with structural components. EPS formed from sucrose during
fermentation can replace hydrocolloids, currently used as dough and bread improvers.
However, it has to be considered that the metabolism of the sourdough microflora can
also have negative impacts on the bread quality, i.e., increased acidification compro-
mises crumb structure and masks beneficial effects of EPS. An improved knowledge of
metabolites formed during sourdough fermentation and their interaction with the dough
components enables a more direct optimization of the resulting bread quality. The stud-
ies presented in this review demonstrate that the use of an optimized sourdough process
in the production of bread provides a feasible technology for producing breads with
improved texture, volume, and shelf life. Sourdough technology can be useful to reduce
or eliminate the level of additives often used in baked products, and furthermore helps
to meet consumer demands for clean labels, natural products, and reduced costs.
References
1. Arendt EK, Ryan LAM, Dal Bello F (2007) Impact of sourdough on the texture of bread. Food
Microbiol 24:165-174
2. Shewry PR, Halford NG, Tatham AS (1992) High molecular weight subunits of wheat glutenin.
J Cereal Sci 15:105-120
