As well as a flavour enhancer, salt plays many other important roles in dough development.
Salt is dissolved in the aqueous phase of the dough. Many bread manufacturers use brine to ensure full dissolution. This affects the viscosity of the dough as some non-gluten-forming proteins (present in flour) are soluble in saline solution, but not in pure water. As more ingredients dissolve into the aqueous phase, dough viscosity increases.
Yeast fermentation is controlled by salt levels, which alter the osmotic pressure in the aqueous phase of the dough. As pressure increases, the water within the yeast cell migrates into the dough and is replaced by the saline solution. This reduces gas production and can kill the yeast cell. This is why yeast and salt are kept separate when initially placing ingredients into the mixer.
Salt can bind around 11 times its own weight in water. This reduces the growth of micro-organisms, which can only access free water, and extends the mould-free shelf life of the product.
Kate Woods, bakery technologist, Campden BRI
Campden BRI provides technical support to the food, drinks and allied industries worldwide. Its activities are built on a programme of industrial relevant research and innovation steered by industry. See campdenbri.co.uk or telephone 01386 842000