A study by the Canadian University of Alberta, Edmonton, showed that sourdough bread differs from ordinary bread in having an extra fermentation step mediated by lactic acid-producing bacteria, over and above yeast fermentation.
"These bugs convert the linoleic acid in sourdough bread flour to a compound that has powerful anti-fungal activity, making preservatives unnecessary," said Michael Gaenzle, who led the study.
"In the study, we offered linoleic acid to lactobacilli and screened for organisms producing potent antifungal activity," he added. "The identification was a bottleneck in the research project. In collaboration with analytical chemists, we had to develop novel methods for identifying the compounds."
According to results of the study, the benefits are better tasting and healthier breads, through the elimination of preservatives and through new production and malting techniques to control fungi via treatment of seeds with the anti-fungal fatty acids produced by the bacteria.