Yeasts are without doubt the most important microorganisms for people since the dawn of history. The ancient Egyptians baked bread with yeast almost 6000 years ago.
There are innumerable species of yeast in nature. The microorganism called ”Saccharomyces cerevisiae” is the one most common, used since ancient times to produce beer, wine and bread.
It is said that an Englishman called Mason prepared the first cake of fresh yeast in 1792. Contrarily, there are also some records which point to fresh yeast being produced in Holland in 1781. The undeniable truth is that the path to commercial production of yeast was based on the finding of Louis Pasteur that “a micro-organism causes fermentation” in 1859. The first commercial packaged baker’s yeast reached the market in 1868.
Active dry yeast was developed during the Second World War, addressing the needs of the battlegrounds. Instant yeast was developed much later, during the 1970s.
Yeast is a type of one-celled micro-organism found commonly in nature. There are innumerable species of yeasts. Saccharomyces cerevisiae is the most familiar species. Yeast multiplies by budding, and need sugar for growth as a carbon source. It also consumes oxygen, nitrogen, phosphorus, various minerals and vitamins. Molasses is the main raw material used in industrial production of yeast because molasses can provide almost all nutrition needs of yeast cells.
Yeast is special because it can be utilised in baking of bread owing to the peculiarities of its metabolism. It is also used in other production requiring fermentation.
Bread dough incorporates sugars, carbonhydrates and other nutritive materials. When yeast is added to dough, the dormant cell wakes up and becomes active, consuming the sugar in the medium and exhaling carbon dioxide gas. This gas causes the dough to rise.
Yeast has many physiological characteristics which make it very useful in the field of biotechnology. Its many usages are in the fermentation industry, biomedical research, environmental technologies, chemical, food and health products industries.