Manufacturing food products by fermentation: ferments

The manufacture of food products involves the use of plant, animal or mineral raw materials, which are transformed by physical means (mechanical, such as grinding or mixing, heat, cold, etc.), physico-chemical (modifying water activity by salting or sweetening, modifying pH by acidification, etc.), biochemical (enzymes, various stabilizers, antioxidants, etc.) or microbial.

The subject of this article is the use of microbial actions that occur naturally or are induced by seeding selected flora.

After a brief reminder of the objectives of these actions, a rapid study of the metabolism of micro-organisms will lead us to consider, in a second article, the important stages in the control of biological processes, as well as the criteria and parameters for action which can be modulated and which need to be reasoned about when implementing a production process. We conclude with a look at the various sectors where fermentations are used in production.

In food processing, micro-organisms can have the following effects:

• flavoring ;

• texture modification ;

• influence on exterior appearance ;

• improved nutritional characteristics ;

• stabilization and conservation.

Some of these effects result from metabolic action of the fermentative type. Others result from the production of exo- or ectocellular enzymes, bioconversions or the metabolic elimination of certain product molecules.

In order to better understand our subject, it is necessary in this first fascicle to understand microbial metabolism and what fermentations are, before presenting, in a second fascicle, the diversity of applications and the conditions to be met.