Abstract
Bakeries use sourdoughs to improve bread properties such as flavor and
shelf life. The degradation of gluten proteins during fermentation may,
however, crucially alter the gluten network formation. We observed
changes that occurred in the HMW glutenins during wheat sourdough
fermentations. As fermentation starters, we used either rye sourdough or
pure cultures of lactobacilli and yeast. In addition, we incubated
wheat flour (WF) in the presence of antibiotics under different pH
conditions. The proteolytic activities of cereal and sourdough‐derived
proteinases were studied with edestin and casein. During sourdough
fermentations, most of the highly polymerized HMW glutenins degraded. A
new area of alcohol‐soluble proteins (≈30.000 MW) appeared as a result
of the proteolytic breakdown of gluten proteins. Very similar changes
were observable as WF was incubated in the presence of antibiotics at pH
3.7. Cereal and sourdough‐derived proteinases hydrolyzed edestin at pH
3.5 but showed no activity at pH 5.5. An aspartic proteinase inhibitor
(pepstatin A) arrested 88–100% of the activities of sourdough enzymes.
According to these results, the most active proteinases in wheat
sourdoughs were the cereal aspartic proteinases. Acidic conditions
present in sourdoughs create an ideal environment for cereal aspartic
proteinases to be active against gluten proteins.
Original language | English |
---|---|
Pages (from-to) | 87-93 |
Journal | Cereal Chemistry |
Volume | 81 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2004 |
MoE publication type | A1 Journal article-refereed |