Fermentation (food):

Fermentation in food processing typically is the conversion of carbohydrates to alcohols and carbon dioxide or organic acids using yeasts, bacteria, or a combination thereof, under anaerobic conditions. A more restricted definition of fermentation is the chemical conversion of sugars into ethanol. The science of fermentation is known as zymology.

History

Since fruits ferment naturally, fermentation precedes human history. Since ancient times, however, humans have been controlling the fermentation process. The earliest evidence of winemaking dates from eight thousand years ago, in Georgia, in the Caucasus area.^[1] Seven-thousand-year-old jars containing the remains of wine have been excavated in the Zagros Mountains in Iran, which are now on display at the University of Pennsylvania.^[2] There is strong evidence that people were fermenting beverages in Babylon circa 5000 BC,^[3] ancient Egypt circa 3150 BC,^[4] pre-Hispanic Mexico circa 2000 BC,^[3] and Sudan circa 1500 BC.^[5] There is also evidence of leavened bread in ancient Egypt circa 1500 BC^[6] and of milk fermentation in Babylon circa 3000 BC.

French chemist Louis Pasteur was the first known zymologist, when in 1854 he connected yeast to fermentation. Pasteur originally defined fermentation as "respiration without air". Pasteur performed careful research and concluded;

Contributions to biochemistry

When studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that the fermentation was catalyzed by a vital force, called "ferments," within the yeast cells. The "ferments" were thought to function only within living organisms. "Alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells,"^[7] he wrote.

Nevertheless, it was known that yeast extracts ferment sugar even in the absence of living yeast cells. While studying this process in 1897, Eduard Buchner of Humboldt University of Berlin, Germany, found that sugar was fermented even when there were no living yeast cells in the mixture,^[8] by a yeast secretion that he termed zymase.^[9] In 1907 he received the Nobel Prize in Chemistry for his research and discovery of "cell-free fermentation."

Uses

The primary benefit of fermentation is the conversion of sugars and other carbohydrates, e.g., converting juice into wine, grains into beer, carbohydrates into carbon dioxide to leaven bread, and sugars in vegetables into preservative organic acids.

Fermented foods by region

Fermented foods by type

Bean-based

Grain-based

Vegetable-based

Fruit-based

Honey-based

Dairy-based

Fish-based

Meat-based

Risks of consuming fermented foods

Food that is improperly fermented has a notable risk of exposing the eater to botulism.

Alaska has witnessed a steady increase of cases of botulism since 1985. Despite its small population, it has more cases of botulism than any other state in the United States of America.^[12] This is caused by the traditional Eskimo practice of allowing animal products such as whole fish, fish heads, walrus, sea lion and whale flippers, beaver tails, seal oil, birds, etc., to ferment for an extended period of time before being consumed. The risk is exacerbated when a plastic container is used for this purpose instead of the old-fashioned method, a grass-lined hole, as the botulinum bacteria thrive in the anaerobic conditions created by the air-tight enclosure in plastic.^[12]

Fermentation (food)

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