Fermentation

FERMENTATION
Preservation of foods by fermentation is a widely practiced and ancient technology. Fermentation ensures not only increased shelf life and microbiological safety of a food but alsomakes some foods more digestible. Lactic acid bacteria because of their unique metabolic characteristics are involved in many fermentation processes of milk, meats, cereals and vegetables. Microorganismsused in the production of cultured dairy products such as yogurt and cheese are called starter cultures. As these microorganisms grow in milk, they convert lactose into lactic acid. During ripeningof the product, the enzymes produced by the starter culture’s microorganism, are responsible for the final product's aroma, taste, and texture. Starter culture also prevents growth of undesirableorganisms.
Bread has been baked since ancient times. Bread making also depends on the activities of yeast called Saccharomyces cerevisiae. Bread dough puffs up because of carbon dioxide, which is aby-product of fermentation. The production of carbon dioxide by yeast is needed to make the dough rise, or increase in volume. This process is called leavening. Leavening makes the dough lighter andmore easily digested. Yeast cells also produce different types of organic acids and alcohol, which makes bread taste better. Baking evaporates any alcohol and deactivates the yeast. It also causesbubbles of carbon dioxide to move through the dough, giving the bread a spongy texture after baking.

Pickled Vegetables: The vegetable is soaked in a salt brine, allowing the growth of bacteria that eatthe vegetable’s sugars and produce tart-tasting lactic acid.

Wines: Yeasts, added to crush grapes, eat the grapes’ sugars and produce alcohol.

Breads: Yeasts, added to dough, digest sugars(derived from starches in dough) and produce carbon dioxide, causing the dough to rise.

Cheeses: Milk bacteria digest the milk sugar lactose and produce lactic acid, which acts with the added...