Fermented foods are now considered by everyone to be useful and healthy for people’s well-being. What gives these food products beneficial properties is precisely the fermentation to which they are subjected. This is a biochemical process, which occurs mainly under anaerobic conditions, carried out by specific bacteria, added industrially or naturally present in foods, which derive energy from the transformation of sugars contained in the food.
Fermentation, in addition to enriching the food matrix with bioactive compounds, is also one of the oldest and best-known food preservation techniques. Fermentation products such as alcohol, acetic acid and lactic acid give foods their characteristic fragrance and are excellent substances capable of prolonging their shelf life.
The beneficial properties that fermentation brings to foods
There are numerous beneficial properties that fermentation brings to foods, let’s explore some of them:
Increased digestibility. This is the case with yogurt in which, thanks to the action of added bacteria, most of the lactose present is split into its constituents, namely galactose and glucose, thus making it more digestible even for those who are intolerant;
Increased production of bioactive peptides. Bioactive peptides are protein compounds of limited size with few amino acids (maximum 20) which, in addition to having nutritional value, modulate some physiological functions of the body through binding to cell receptors that regulate specific metabolic processes. They can also exert ACE-inhibitory, opioid (thus exercising their effect at the nervous system level), immunostimulant, antioxidant action and decrease serum cholesterol levels;
Increased levels of conjugated linoleic acid. Especially in food matrices of dairy origin, fermentation leads to a compound capable of exerting beneficial effects on the lipid profile, on immune system activity and developing anti-carcinogenic activity;
Increased bioavailability and bioactivity. The fermentation process favors the release of polyphenols that are usually present in food in the form of complexes and that are now able to exercise their antioxidant activity in an enhanced manner;
Vitamin synthesis. Fermentation leads to the production of some B vitamins (folic acid, riboflavin and vitamin B12), therefore, it further enriches foods with bioactive compounds precious for the organism;
Elimination of anti-nutrients. The fermentation process reduces the presence of substances in food that are able to interfere with the absorption and bioavailability of some minerals. An example of this type of substance are phytates which exert a chelating action against iron, zinc and copper;
Probiotic action. Many of the lactic bacteria responsible for fermentation processes in foods are able to reach and colonize the colon environment, favoring the balance of intestinal flora and exerting multiple beneficial effects at gastrointestinal and systemic levels. They are also able to coexist with the host according to a symbiotic relationship in which both benefit from each other;
Prebiotic action. During fermentation, polysaccharides can be produced which are then used as metabolic substrate by the flora present in the colon.
The most widespread fermented foods
Fermented foods are now a universal resource, although some countries such as Japan, China, Korea, Vietnam and Germany have always had a gastronomic culture based on these foods. Below we report a list of some of the most widespread fermented foods:
Yogurt: it is one of the best-known fermented foods, obtained thanks to the inoculation of lactic bacteria that trigger the milk fermentation process. This produces a more easily digestible product, with enhanced nutritional properties and with now established benefits both at gastrointestinal and immune levels. Lactic bacteria also have the ability to synthesize substances with antimicrobial action (called bacteriocins) which, in synergy with lactic acid production, contribute to blocking the action of any pathogens and increasing food safety and healthiness;
Kefir: it is a beverage originating from the Caucasus, obtained through milk fermentation by a combination of lactic bacteria and yeasts (called Kefir grains formed by a polysaccharide called kefiran that hosts colonies of bacteria and yeasts in symbiotic association) for a period between 24 and 48 hours. Also in this case, the ability to modulate inflammatory and immune processes is known;
Miso: originating from Japan, it is a food obtained from yellow soy beans, which is cooked and fermented with a fungus known as Aspergillus oryzae. This food, with a pasty consistency and high content of proteins and B vitamins, is mainly used as a seasoning for soups;
Sauerkraut: it is a typical side dish of German culture obtained from finely cut cabbage and subjected to controlled lactic fermentation for about two months. Fermentation is mainly exploited as a preservation technique, but gives the food its distinctive and sour taste while enriching it with vitamins and mineral salts.
Conclusions
In the past, the health benefits provided by fermented foods were unknown. People mainly used fermentation to preserve foods and improve their taste, while today it is used to enrich them with functional properties such as probiotic, antimicrobial, antioxidant, anti-inflammatory ones.
Consuming fermented foods, rich in probiotics and prebiotics, is useful for the health of the intestinal microbiota and digestive system, but also for the cardiovascular and immune systems. Yogurt, Kefir, Miso, Sauerkraut are just some of the fermented foods that are now part of our diet and all have beneficial properties for health.
