Why sourdough bread resists mold

Feb 21, 2013

Sourdough bread resists mold, unlike conventionally leavened bread. Now Michael Gaenzle and colleagues of the University of Alberta, Edmonton, show why. During sourdough production, bacteria convert the linoleic acid in bread flour to a compound that has powerful antifungal activity. The research, which could improve the taste of bread, is published online ahead of print in the journal Applied and Environmental Microbiology.

The major benefits from the research are twofold: better tasting bread, says Gaenzle, because "preservatives can be eliminated from the recipes, and because has a more distinct and richer flavor compared to bread produced with yeast only;" and novel tools to control fungi in malting and plant production, via treatment of seeds with the anti-fungal .

Genuine sourdough bread differs from ordinary bread in having an extra fermentation step, over and above yeast fermentation. This step is mediated by , typically of the genus Lactobacillus, says Gaenzle.

In the study, "we offered linoleic acid to lactobacilli and screened for organisms producing potent antifungal activity," says Gaenzle. The investigators then fractionated the to isolate and identify compounds with antifungal activity. "The identification was a bottleneck in the research project," says Gaenzle. "In collaboration with analytical chemists, we had to develop novel methods for identifying the compounds."

L. hammesii produced substantial quantities of hydroxylated monounsaturated fatty acids which the researchers found strongly inhibited mold formation. A second antifungal fatty acid produced by cereal enzymes contributes to the antifungal activity of sourdough.

"The two compounds and their formation by cereal or microbial enzymes had been described previously, but their antifungal activity and their generation in food production was unknown," says Gaenzle. These new findings, he says, were "a step towards understanding how and why lactobacilli metabolize fatty acids. This could be useful in the long term to improve our understanding of the biology of these organisms."

Explore further: Two-armed control of ATR, a master regulator of the DNA damage checkpoint

More information: Formal publication of the article is scheduled for the second March 2013 issue of Applied and Environmental Microbiology. bit.ly/asmtip0213a

add to favorites email to friend print save as pdf

Related Stories

Making whole wheat bread taste and smell more appetizing

Jan 09, 2013

The key to giving whole wheat bread a more appetizing aroma and taste may lie in controlling the amounts of a single chemical compound that appears in the bread, which nutritionists regard as more healthful ...

Old recipe making a come back

Dec 05, 2011

Humans ate sourdough bread in ancient times and it's remained a traditional part of the diets in some countries and regions. Now Baltic scientists have reinvented this centuries-old technique for the needs of the food industry ...

Recommended for you

Japanese scientist resigns over stem cell scandal

Dec 19, 2014

A researcher embroiled in a fabrication scandal that has rocked Japan's scientific establishment said Friday she would resign after failing to reproduce results of what was once billed as a ground-breaking study on ...

'Hairclip' protein mechanism explained

Dec 18, 2014

Research led by the Teichmann group on the Wellcome Genome Campus has identified a fundamental mechanism for controlling protein function. Published in the journal Science, the discovery has wide-ranging implications for bi ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.