Products
Fermented foods are available in grocery stores and are also homemade.
Structure and properties
Fermented foods are foods that have been subjected to fermentation, which is a microbiological breakdown of ingredients by living bacteria or fungi. Well-known examples of such microorganisms are lactobacilli (lactic acid bacteria), yeast fungi such as and molds such as . However, countless other species have been identified in fermented foods. The microorganisms are either already present on the food (spontaneous fermentation) or they are added in the form of starter cultures. Living microorganisms may still be present in the final product. Depending on the product, they can also be removed with filtration, for example, or inactivated with heat.
Examples of fermented foods
The starting materials are in parentheses:
- Apple cider, cider (apple juice).
- Asian products such as miso (including soybeans), kimchi (Chinese cabbage), kombucha (sweetened black or green tea) and natto (soybeans).
- Beer (cereals such as barley)
- Bread (flour)
- Vinegar (eg wine, apple juice)
- Hard cheese, blue cheese (milk)
- Pu-erh (tea leaves)
- Salami, dried meat (meat)
- Pickled cucumbers (gherkins)
- Sauerkraut (cabbage)
- Sour cream (milk)
- Sauser (grape juice)
- Chocolate (cocoa seeds)
- Soy sauce (soybeans, cereals)
- Yogurt (milk)
- Wine (grape juice)
Effects
During fermentation, new chemical compounds are formed. For example, during yeast fermentation, carbohydrates are metabolized by the fungi to ethanol and carbon dioxide. Sweet grape juice is thus turned into psychoactive wine. Both beverages have different compositions and properties. Fermentation makes some foods digestible. For example, flour, which rises during bread production, acquires a new consistency and forms aromatic substances. The taste and texture are essential reasons for the fermentation of food. Fermentation is based on the metabolism of microorganisms. It is catalyzed by microbial enzymes and is used by fungi and bacteria to obtain energy and nutrients, among other things. An important function of fermentation is the preservation of rapidly perishable foods. On the one hand, foods that have already been fermented often cannot be fermented any further because the substrates have already been consumed by the bacteria and fungi. On the other hand, natural preservatives such as organic acids (e.g. acetic acid, lactic acid) and the alcohol ethanol are formed during this process. As a result, the pH value usually decreases, i.e. the products become more acidic. Furthermore, the water content also decreases. The presence of water is an important prerequisite for the growth of microorganisms. Fermented foods can therefore sometimes be stored for years or even decades! Fermented foods can exert health-promoting effects. They can contain lactobacilli and other bacterial strains, which belong to the probiotics and mediate positive effects in the intestine. Another advantage is that potentially intolerable ingredients such as FODMAP are degraded by them and do not trigger disorders in the intestine. Finally, the microorganisms can also form substances that exert beneficial effects.
Areas of application
As food, stimulant and intoxicant.
Adverse effects
Because of the diversity of fermented foods, general statements about adverse effects are difficult. They can be both better and worse tolerated than unfermented foods. Fermented foods may contain histamine and other biogenic amines, which cause adverse effects in people with food intolerance (see also under histamine intolerance). Vasoactive biogenic amines are associated with other side effects. In the case of spontaneous fermentation, it cannot be ruled out that undesirable molds and bacteria proliferate, forming mycotoxins and bacterial toxins.