Fermentation (food)

Fermentation in food processing is a metabolic process that converts carbohydrates to alcohol or organic acids using microorganisms—yeast or bacteria—under anaerobic conditions. This process not only enhances food preservation but also can improve the nutritional value and flavor of foods.

Definition and Process

Fermentation typically refers to the chemical conversion of sugars into ethanol in the production of alcoholic beverages like wine, beer, and cider. It is also critical in bread making, where the CO₂ produced by yeast activity causes the dough to rise. In the preservation of sour foods, lactic acid is produced, as seen in sauerkraut and yogurt. Other fermented products include vinegar, olives, and cheese.

History and Prehistory

Fermentation is an ancient technique, predating human history. Earliest evidence suggests the process was used 13,000 years ago in what is now Israel to make a primitive form of beer. In the Neolithic period, a form of alcoholic beverage from fruit, rice, and honey was produced in China, and winemaking traces back to 6000 BC in Georgia.

Discovery of the Role of Yeast

In 1856, Louis Pasteur connected yeast to fermentation and founded zymology, the study of fermentation. He discovered that fermentation was catalyzed by what he termed "ferments" in yeast cells, which facilitated the chemical conversion of sugars to alcohol.

Cell-Free Fermentation

The concept of "cell-free fermentation" came about when Eduard Buchner found that yeast extracts could ferment sugar even without living yeast cells, due to an enzyme complex secreted by yeast called zymase. Buchner's work earned him the Nobel Prize in Chemistry in 1907.

Health Benefits

Fermented foods are often rich in probiotics, which can enhance digestive health. They are also associated with improved absorption of nutrients and may contribute to a stronger immune system.

Culinary Uses

Fermented foods play a crucial role in culinary traditions worldwide, providing unique flavors and textures to various dishes.

See Also

• History of biochemistry
• History of bread
• Probiotics
• Microbiology