The fermentation It is a catabolic process carried out by some organisms through which they obtain energy through the degradation of compounds. It is an incomplete oxidation process.
Fermentation is a anaerobic process, since it is done without the presence of oxygen. It is carried out in some cells of living beings and in organisms such as yeast and bacteria. These organisms obtain energy (although less than in aerobic respiration) by breaking down organic molecules, such as starch or sugar, resulting in a simpler organic compound. For instance: Yeasts ferment the sugars in grapes and convert them to alcohols in wine production.
The fermentation process was discovered by the French chemist, Louis Pasteur, who revealed that fermentation was a natural process resulting from the development of microorganisms. This fermentation occurs naturally, although in industry fermentation can be oxidative, that is, in the presence of oxygen.
There are different types of fermentation that produce many of the foods and beverages that humans consume. For instance: beer, wine, yogurt, soy sauce. Many acids obtained through fermentation are those that allow the preservation of food for a longer time (without losing its qualities and characteristics).
Types of fermentation
- Alcoholic fermentation. It is a type of fermentation in which yeasts convert glucose, sucrose, and fructose into ethanol. In this process, which occurs in the absence of oxygen, microorganisms obtain energy and produce alcohol and carbon dioxide. This fermentation is used in the production of alcoholic beverages such as wine, cider and beer.
- Acetic fermentation. It is a type of fermentation that requires oxygen. In this fermentation, the bacteria transform ethyl alcohol into acetic acid. This acid is used in the production of vinegar.
- Butyric fermentation. It is a type of anaerobic fermentation. In this fermentation, carbohydrates are converted into butyric acid by the action of bacteria. It is characterized by its smell.
- Lactic fermentation. It is a type of anaerobic fermentation in which bacteria obtain energy by metabolizing sugars and converting them into lactic acid. It also occurs in some tissues of animal cells such as muscle tissue. This type of fermentation is used for food preservation.
- Butanediol fermentation. It is a type of fermentation carried out by bacteria that form carbon dioxide and butanediol alcohol.
- Propionic fermentation. It is a type of anaerobic fermentation carried out by bacteria. They ferment sugars and obtain propionic acid, acetic acid and carbon dioxide.
Fermentation Examples
- Wine making. It is a type of alcoholic fermentation. In winemaking, the sugars present in the must (grape juice) are transformed into alcohol by the intervention of yeasts present in the grape. Carbon dioxide is also produced.
- Preparation of yogurt. It is a type of lactic fermentation. In the production of yogurt, milk (usually cow’s) is fermented. Bacteria use lactose as an energy source that is released in the form of lactic acid.
- Preparation of sauerkraut. In the production of sauerkraut, bacteria produce lactic acid through lactic fermentation. Bacteria consume the sugar in cabbage and produce lactic acid, acetic acid, ethanol, and carbon dioxide.
- Bread making. In bread making, the starch in the flour is transformed, by means of yeast, into glucose. Carbon dioxide is also produced responsible for the bread to puff up.
- Making soy sauce. In the production of soy sauce, soybeans are boiled with toasted wheat. The action of a fungus produces a lactic acid fermentation and an alcoholic fermentation.
- Cheese making. It is a type of lactic fermentation. In cheese making, bacteria produce lactic acid from lactose.
- Brewing beer. It is a type of alcoholic fermentation. In brewing, yeast converts the sugars in barley wort into alcohol.
- Preparation of the masato. It is a type of drink that is produced from alcoholic fermentation. It is obtained from cassava, rice or corn. Yeast is used that transforms the sugars contained in these foods into alcohol.
- Rice wine making. Rice wine is obtained by fermenting rice. Fermentation consists of two stages. In the first, the starch of the rice is transformed into sugar (by means of bacteria); in the second, the sugar is transformed into alcohol.
- Preparation of vinegar. In making vinegar, bacteria ferment the ethyl alcohol in wine, transforming it into acetic acid.