Spoilage
In addition to many other properties, lactic acid bacteria generate antimicrobial substances that play an important role in food safety and preservation. Industrial bread manufacturers use chemical preservatives such as calcium propionate, which may be a carcinogen, to help prevent spoilage.
Furthermore, the lactic and acetic acids that build up as the lactic acid bacteria work act as a natural preservative (in the sense of mould inhibitor) and thus avoiding the need for chemicals. So, even if the bread stales it is toastable days and days after it is made.
Removal of harmful agents and coeliac disease
The most interesting recent research, with considerable implications for making our daily bread wholesome again, has shown that lactic acid bacteria are capable of de-activating the very substances that cause wheat allergy and coeliac disease.
In 2002 Italian scientists demonstrated for the first time that selected sourdough lactic acid bacteria could neutralise some of the wheat gliadin (a component of gluten) that causes an auto-immune response which attacks the intestinal mucosa of coeliacs interfering with their absorption of nutrients.
In 2004 a Japanese study showed how the lactic fermentation of soy sauce completely removes any allergens from wheat, which is one of its two main ingredients.
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This is no mean feat, since other studies have proved that particular parts of the wheat gliadin that harm humans are hardly affected at all by stomach enzymes and very acidic gastric and duodenal fluids. It seems to be the unique property of certain lactic acid bacteria that, given time, they can knock out some otherwise impervious elements that make wheat unpalatable for so many people.
13 out of 17 patients showed a marked alteration of intestinal permeability (popularly known as “leaky gut”) after eating yeast-raised bread. But the same 13 patients, when fed sourdough bread, showed no significant reaction: remarkably, coeliacs had eaten bread with wheat in it with no ill effects. (The remaining 4 did not respond to gluten in either of the breads).
The authors of the experiment conclude, rather modestly, that bread made using selected lactobacilli and a long fermentation time “is a novel tool for decreasing the level of gluten intolerance in humans”. Currently, the only treatment for coeliac disease is a lifetime abstention from gluten.
This experiment is a ray of hope for coeliacs. It suggests that everyone should be able to eat wheat and rye bread if we get the bread making right.
What’s more it may point to how cereal intolerance is not so much a matter of genetic chance as a consequence of the reckless application of scientific knowledge in the service of private gain rather than public health.
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