Fermentation is an anaerobic process, when the final acceptor of electrons is an organic mixture.
From a technological point of view, a fermentation is a metabolic process producing energy, end-products and aromatic compounds.
Some examples of fermentation:
alcoholic fermentation
lactic fermentation
propionic fermentation
malolactic fermentation
acetic fermentation (a respiration).

Why use fermentation?
1. end products can inhibit the growth of spoiling microorganisms; moreover, the oxidation of organic compounds is partial, thus raw material contain “enough potential energy for consumers” ( Caplice and Fitzgerald, 1999).
2. end products contribute to flavour, aroma and texture.
3. fermentation also can improve the nutritional quality of the food, increasing the digestibility, like in the case of the fermentation of the milk for the production of cheese.
4. fermentation can reduce the toxicity of some foods like in “gari”.