Sourdough bread ingredients

Fumaric acid breaks the sulfur-to-sulfur bonds in the elastic protein gluten in bread doughs. This makes the doughs more machine-able. It also is a key ingredient in rye and sourdough breads—it makes them sourer. 

LA may also be found in various processed foods, usually either as a pH-adjusting ingredient or as a preservative (either as antioxidant or for control of pathogenic micro-organisms). It may also be used as a fermentation booster in rye and sourdough breads. 

Carboxylic acids have a distinctly sour taste that we associate with vinegar or citrus products. Acetic acid is the active ingredient in vinegar and gives sourdough bread its bite. 

Like all acids, carboxylic acids taste sour. The most familiar carboxylic acid is ethanoic acid, better known by its common name, acetic acid. Acetic acid is the active ingredient in vinegar. It can form by the oxidation of ethanol, which is why wines left open to air become sour. Some yeasts and bacteria also form acetic acid when they metabolize sugars in bread dough. These are added to bread dough to make sourdough bread. Other common carboxylic acids include methanoic acid (formic acid), present in bee stings and... 

Rizzello, C. G., Cassone, A., Coda, R., Gobbetti, M. (2011). Antifungal activity of sourdough fermented wheat germ used as ingredient for bread making. Food Chemistry, 127, 952-959. 

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