Fermented Foods: Definition, Types, Examples, Application and Benefits
What are fermented food?
Fermented foods are defined as meals and drinks that have experienced controlled fermentation, a process in which sugars and other chemicals are transformed into acids, gasses, or alcohol by microorganisms such yeasts, bacteria, and molds. Along with helping to generate probiotics and other healthy nutrients, this biochemical process improves the food's texture, taste, and shelf life. Cultures have used fermentation for thousands of years to preserve and improve food. Generally, fermentation occurs in anaerobic environments.
Fermentation foods may be classified into two divisions: aerobic fermentation, including fungal and alkaline processes, and anaerobic fermentation, including alcoholic and lactic acid processes. Microbial fermentation involves the breakdown of fermentable carbohydrates into end products like organic acid, carbon dioxide, and alcohol. Additionally, it produces anti-microbial metabolites such bacteriocins, which enhance food safety by either eliminating or suppressing food-borne infections. In addition to extending the shelf life of highly perishable foods, fermentation also improves the organoleptic qualities of food, the digestibility of proteins and carbohydrates, and the bioavailability of vitamins and minerals.
Bioactive compounds and valuable products recovered from several sources of fermented foods. (Faria D J., et al., 2023)
Types of fermented foods
Fermented milk and milk products
Cheese: It is an intrinsically superior fermented dairy product characterized by its substantial calorie content and abundant levels of fat, protein, calcium, and vitamin B. Throughout the process of cheese manufacturing, milk, rennet, starter culture, and pro-teases and peptidases derived from secondary microbial flora are employed to enzymatically degrade casein and generate bioactive chemicals that manifest a diverse array of biological effects. The vitamin and mineral composition of cheese, together with its bioactive peptides (such as antihypertensive, antioxidant, opioid, anti-proliferative, antimicrobial peptides, and conjugated linoleic acids (CLA)), primarily contribute to its disease prevention and treatment properties.
Yogurt: It is the most well recognized food containing probiotics, is a coagulated dairy product produced by fermenting Lactobacillus bulgaricus and Streptococcus thermophiles with lactic acid.
Koumiss: It is a somewhat alcoholic fermented beverage derived from unpasteurized mare's milk. Koumiss originated with Asian nomads and is currently widely consumed in western and central Asian countries such as Kazakhstan, Mongolia, Kyrgyzstan, and Russia.
Kefir: It is an ancient fermented milk beverage with a sour, acidic, and faintly alcoholic flavor and a creamy texture. It originated in the Caucasus and is made from the acid-alcoholic fermentation of milk by microorganisms found in kefir grains. Acid-alcoholic fermentation is caused by a mixture of yeast, acetic acid, and lactic acid bacteria strains.
Generalized flow chart for manufacture of fermented dairy products. (Tamang J P., et al., 2020)
Fermented meat and meat products
The most ancient and extensively used form of fermentation is the fermentation of meat. Fermented meat products are characterized by their distinctive flavor, color, aroma, and odor as a result of numerous biochemical, microbiological, and chemical alterations that occur during the production process. Lactic acid bacteria, which are crucial to the fermentation of meat, reduce pH and generate bacteriocins that inhibit the proliferation of pathogenic and decomposing microorganisms. Consequently, the safety, stability, and shelf life of fermented meat products are enhanced.
Fermented fruit and vegetable products
Due to the ease with which untreated fruits and vegetables deteriorate, fermentation, the oldest method of preserving them, is highly favored. An essential component of human nutrition worldwide are fermented fruits and vegetables, including sauerkraut, kimchi, pickled cucumbers, and fermented olives. When the conditions are conducive to lactic acid bacteria (LAB), the predominant microorganism in this form of fermentation, the fermentation of fruits and vegetables is primarily lactic acid fermentation, which occurs spontaneously. Antioxidants in fermented fruits and vegetables can assist in the elimination of hazardous free radicals that contribute to the development of degenerative diseases, while probiotics in fermented fruits and vegetables with lactic acid bacteria can reduce the risk of certain diseases, including cirrhosis and diarrhoea.
Fermented fish products
Fermentation of fish results in the production of desirable organoleptic properties, including a desirable aroma, texture, and flavor. However, fermented fish products have also been demonstrated to have beneficial nutritional value. For instance, the consumption of fermented fish by chickens leads to a reduction in cholesterol concentration, an increase in DHA concentration, and a favorable n-6/n-3 ratio in the eggs they produce.
Fermented legume-based foods
Fermented products that are derived from legumes are consumed on a global scale. Fermentation enhances the flavor, appearance, nutrient digestibility, nutritional value, texture, and shelf life of legumes, while protease inhibitors, lectins, oligosaccharides, and phytates, which are non-nutritive compounds found in legume seeds, are reduced. Furthermore, the fermentation of legumes results in an increase in the concentration of phenolic compounds in the legume seeds. Fermented legumes demonstrated anti-diabetic properties by modulating certain enzymes, including acetylcholinesterase, glucosidase, and amylase, and by functioning as antioxidants.
Fermented soybean products
Fermented soybeans are a significant source of nutrition in the diets of China, Korea, and Japan. Miso, a fermented soybean paste, is a soybean mélange that is rich in microorganisms, carbohydrates, lipids, sodium, vitamins, minerals, and vegetable protein. Miso functions as an ACE inhibitor, an estrogen-like substance, and a scavenger of reactive oxygen species in humans. It is a traditional non-salted fermented delicacy that is primarily consumed in Japan and is produced from the fermentation of soybeans by Bacillus subtilis natto. This bacterium produces proteases that degrade proteins into peptides and amino acids. Natto is another traditional fermented soybean product.
Applications of fermented foods
Food Preservation: Fermentation is one of the oldest ways to preserve food. The formation of acids, alcohols, and gasses during fermentation produces an environment unsuitable for spoilage-causing microbes, increasing the food's shelf life. Sauerkraut, pickles, and fermented dairy products are examples of foods that have a long shelf life.
Flavor Enhancement: Fermentation substantially modifies the flavor profile of foods, resulting in sour, umami, and complex flavors. Many culinary traditions rely on fermented foods for their characteristic tastes, such as soy sauce, kimchi, and beer.
Health Foods and Probiotics: Fermented foods are employed in health and wellness applications because they contain probiotics. Probiotic bacteria, present in foods such as yogurt and kefir, promote gut health by balancing helpful microbes in the digestive tract.
Our Services of Fermentation in Human Nutrition
Benefits of Fermented Foods
Improved digestive health: Fermented foods include probiotics, which increase the development of good bacteria in the stomach. These probiotics promote digestion, ease digestive disorders such as bloating and constipation, and may help avoid irritable bowel syndrome (IBS). Regular use of yogurt and kefir, for example, can improve gut health by promoting a healthy microbiota.
Enhanced nutrient absorption: Fermentation degrades antinutrients (compounds that prevent nutrient absorption), such as phytic acid, which is often present in grains and legumes. This procedure increases the bioavailability of nutrients such as vitamins, minerals, and proteins, making it simpler for the body to absorb. Fermented soy products, such as tempeh and miso, contain more amino acids and vitamins than non-fermented counterparts.
Boosted immune function: Fermented foods promote immune health by preserving the gut flora, which is crucial to immunological response. Probiotics in fermented foods improve the intestinal barrier, preventing dangerous germs from entering the circulation. Furthermore, fermented foods like sauerkraut and kimchi include immune-boosting components such as vitamins C and B12.
Antioxidant and anti-inflammatory properties: Compounds found in some fermented foods have anti-inflammatory and antioxidant properties. Kimchi and other fermented vegetables, for instance, are rich in phytochemicals that assist in scavenging free radicals and lowering oxidative stress. These characteristics might help shield against long-term health issues including cancer and heart disease.
References
- Feng R., et al., Fermentation trip: amazing microbes, amazing metabolisms, Annals of microbiology, 2018, 68: 717-729.
- Faria D J., et al., Valorization of fermented food wastes and byproducts: Bioactive and valuable compounds, bioproduct synthesis, and applications, Fermentation, 2023, 9(10): 920.
- Şanlier N., et al., Health benefits of fermented foods, Critical reviews in food science and nutrition, 2019, 59(3): 506-527.
- Tamang J P., et al., Fermented foods in a global age: East meets West, Comprehensive Reviews in Food Science and Food Safety, 2020, 19(1): 184-217.
