Final answer:
True, salt in yeast bread does control the action of yeast, which is essential in regulating yeast metabolism for proper bread texture and flavour. A high concentration of salt can be adaptively managed by yeast, illustrating why salt is vital for controlling the fermentation process in bread-making.
Step-by-step explanation:
True: Salt in yeast bread does indeed control the action of the yeast. This is a crucial aspect in the bread-making process to regulate the rate of fermentation caused by the yeast. In addition, a proper concentration of salt ensures that the yeast metabolism is balanced, preventing it from acting too quickly or too slowly, which is vital for the texture and flavour of the bread.
In the history of artisanal slices of bread, wild yeasts were used, which were less predictable and could lead to many batches of dough being discarded due to inconsistent results. However, Saccharomyces cerevisiae, commonly known as brewer's or baker's yeast, is now used in bread-making. This yeast is particularly valuable because of its ability to consistently produce carbon dioxide gas through alcoholic fermentation, which leavens bread by creating bubbles in the dough, subsequently giving bread its airy texture.
When yeast cells are placed in an environment with a high concentration of salt, such as a 4.0% NaCl solution, they adapt by producing glycerol to counteract the osmotic pressure. This demonstrates how adaptable yeast cells are, and it underscores the importance of salt in controlling the environment to achieve the desired results in bread production.