Yeast Fermentation

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•  Use of anaerobic cell respiration in yeasts to produce ethanol and carbon dioxide in baking

Anaerobic respiration (fermentation) involves the breakdown of carbohydrates in the absence of oxygen

In yeasts, fermentation results in the production of
ethanol and carbon dioxide – which can be used in food processing:

  • Bread – Carbon dioxide causes dough to rise (leavening), the ethanol evaporates during baking
  • Alcohol – Ethanol is the intoxicating agent in alcoholic beverages (concentrations above ~14% damage the yeast)

Bacterial cultures can also undergo fermentation to produce a variety of food products

  • Yogurt / Cheese – Bacteria produce lactic acid anaerobically, which modifies milk proteins to generate yogurts and cheeses

Production of Fermented Foods by Bacteria and Yeast (Saccharomyces)

fermentation products

Link:  TED Talk – The Importance of Bread