Fermentation

In its strictest sense, fermentation (formerly called zymnosis) is the energy-yielding anaerobic metabolic breakdown of a nutrient molecule, such as glucose, without net oxidation. Fermentation yields lactate, acetic acid, ethanol, or some other simple product.

History

Since fruits ferment naturally, fermentation precedes human history. However, humans began to take control of the fermentation process at some point. There is strong evidence that people were fermenting beverages in Babylon circa 5000 BCE, ancient Egypt circa 3000 BCE, pre-Hispanic Mexico circa 2000 BCE, and Sudan circa 1500 BCE. There is also evidence of leavened bread in ancient Egypt circa 1500 BCE and of milk fermentation in Babylon circa 3000 BCE. The Chinese were probably the first to develop vegetable fermentation.

Related Topics:
Babylon - 5000 BCE - Ancient Egypt - 3000 BCE - Pre-Hispanic Mexico - 2000 BCE - Sudan - 1500 BCE

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Products

Yeast produce ethanol and carbon dioxide gas. When the ferment has a high concentration of pectin minute quantities of methanol can be produced. Usually only one of the products is desired; in bread the alcohol is baked out, and in alcohol production the carbon dioxide is released into the atmosphere.

Related Topics:
Ethanol - Carbon dioxide - Pectin - Methanol

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Products produced by fermentation, such as ethanol and lactic acid, are used as a substitute for oxygen. During cellular respiration, oxygen is the final electron acceptor. However, when no oxygen is available, ethanol and lactic acid are used in place of oxygen.

Related Topics:
Ethanol - Lactic acid - Cellular respiration - Oxygen - Electron

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Depending on the type of fermentation, some products (eg: fusel alcohol) are harmful to people's health.

Related Topics:
Fermentation - Fusel alcohol

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Bacteria generally produce acids. Vinegar (acetic acid) is the direct result of bacterial fermentation. In milk, the acid coagulates the casein, producing curds. In pickling, the acid preserves the food from pathogenic and putrefactive bacteria.

Related Topics:
Acetic acid - Casein

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