The main types of microorganisms in fermented foods
1. Bacteria
One type is cocci. Based on their shape, cocci are spherical or similar to spheres. Different arrangements of colonies observed under a microscope as well as variations in the number of cocci can lead to their classification as single, diplococci, or tetracocci. Another type is bacilli. Bacilli are cylindrical or close to cylindrical in shape. Depending on their aggregation, they can be classified as diplobacilli, single bacilli, branched bacilli, or cocci.
2. Fungi
In fermented foods, yeast is a common type of fungus, along with a small amount of mold. A small number of fungal microorganisms are capable of producing alkaline or acidic substances. When metabolizing carbohydrate substances, they can produce aromatic aldehydes and aromatic alcohols. Yeast belongs to the single-celled fungi category and is often used in the fermentation of dough, soy sauce, and other products. Common types of yeast include Saccharomyces cerevisiae and brewing yeast.
In fermented foods, common types of molds include Aspergillus and Penicillium. Probiotics are representative microorganisms found in fermented foods. They are live microorganisms that can have beneficial effects on the host's health. Probiotics exhibit good resistance to bile and gastric acid and can colonize and proliferate in the digestive tract. They are often used in functional fermented foods and are a combination of bifidobacteria and lactic acid bacteria. In recent years, there has been development towards potential probiotics, including acidophilus, spore-forming bacilli, bifidobacteria, brewing yeast, and Streptococcus mutans.
The important components of microorganisms
1. Active Peptides
The important components of microorganisms in fermented foods include active peptides. During food fermentation, the microbial hydrolysis of proteins can lead to the formation of bioactive peptides, which often possess certain functional properties. Probiotic strains of microorganisms can have an impact on the types of amino acids and peptides formed after enzymatic hydrolysis of proteins. Some of these peptides can have antioxidant and antimicrobial properties, while others can have nutritional and flavor-related characteristics. These active peptides often exhibit sensory and physiological effects, primarily related to anti-thrombotic, immune regulatory, antioxidant, and anti-hypertensive activities.
Additionally, they can also regulate mineral absorption. For example, soybean peptides can inhibit the overall activity of angiotensin-converting enzyme, preventing the contraction of vascular smooth muscles and thus helping to reduce blood pressure.
2. Enzymes
During food fermentation, microorganisms promote the formation of enzymes that break down complex compounds into simple molecules, exhibiting good biological activity. Common examples include proteases and Monascus purpureus. These substances can form diverse carbohydrases, including maltase, alpha-amylase, and cellulase, enabling the breakdown of large-molecule sugars in food.
In fermented foods, Bacillus spores, such as Bacillus licheniformis and Bacillus subtilis, can produce amylases. Additionally, Bacillus spores can produce cellulases.
The main functional characteristics of microorganisms in fermented food
1. Enhance antioxidant activity
During the metabolic processes in the human body, an excess of free radicals can be formed. If there are too many free radicals, they can have a negative impact on human health and contribute to aging. However, the antioxidative substances formed during food fermentation can help delay the aging process. Microorganisms such as Monascus and Aspergillus in fermented foods can significantly enhance the antioxidant function of the food.
2. Prevention of hypertension and heart disease
In fermented dairy products, the anti-hypertensive properties are quite apparent. Purple-red koji can inhibit the synthesis of key enzymes to prevent cholesterol production, thus achieving the goal of preventing hypertension. Some fermented bean products also exhibit significant anti-hypertensive properties. Indonesian tempeh and Japanese natto, for example, contain soybean peptides that can resist hypertension. Fermented bean products made in Korea contain soy isoflavones, which can prevent cardiovascular diseases. Whole grain foods, when fermented, can also contribute to the prevention of heart disease. After developing hypertension, regularly consuming fermented bean products can significantly reduce the likelihood of developing cardiovascular diseases.
3. Prevention of gastrointestinal diseases
Fermented dairy products contain active bacteria that can regulate immune function and treat diarrhea. Lactic acid bacteria are effective in treating gastrointestinal diseases and can provide relief for inflammatory gastrointestinal diseases by reducing the duration and severity of flare-ups. Korean kimchi can inhibit inflammatory bowel diseases due to the improvement it brings to the gut microbiota. The intestinal microbiota can produce secondary metabolites that maintain overall health and enhance the overall stability of the immune system in the gut.
4. Alleviating lactose absorption issues
During the production of yogurt, thermophilic streptococci and Lactobacillus bulgaricus can produce a significant amount of β-D-galactosidase, which helps improve lactose absorption in individuals with lactose intolerance. Fresh yogurt can serve as a helpful aid in digestion and enhance the absorption of lactose.
5. Adsorption of harmful substances
The microorganisms in fermented foods can reduce the production of harmful substances. Lactic acid bacteria in brine can inhibit the peroxidation of unsaturated fatty acids, reducing the formation of aldehydes derived from corresponding alcohols. Some lactobacilli can adsorb mycotoxins present in food without affecting their own growth. Among three strains of plant-derived lactobacilli, they possess the strongest capability to absorb aflatoxin, with a binding rate close to 60%. Additionally, lactic acid bacteria can adsorb heavy metal ions, with mercury being a typical representative.
6. Formation of specific food flavors
In fermented foods, flavor is often derived from various volatile compounds. Food flavor primarily results from the combined actions of multiple microorganisms, and there may be variations in flavor compounds during different fermentation periods. The microbial species can vary significantly depending on the brine formulation, leading to differences in flavor compounds. Microorganisms play a crucial role in the formation of flavor compounds.
7. Improving nutritional composition
Vitamin B12 is an essential nutrient that plays a significant role in inhibiting problems such as dementia, depression, and anemia. Fermented bean curd contains a variety of B vitamins, and during the fermentation process, under the influence of microorganisms, it can produce vitamin B12. Through the fermentation with yeast and Rhizomucor miehei, fermented bean curd can also contain melanoidins and soybean peptides.
Additionally, yeast can promote the breakdown of macromolecules such as fats and proteins into free fatty acids and amino acids, transforming them into small-molecule substances. This fermentation process can enhance the presence of essential amino acids, indicating that fermentation can improve the nutritional composition of food.
HSF Biotech Fermented Products in the Food Industry
The utilization of lactic acid bacteria fermentation in the food industry offers exciting possibilities for the production of a diverse range of products. From HSF Biotech Fermented Fruit and Vegetable Powders to Fermented Turmeric Powder, Fermented Ginseng Powder, Fermented Maca Powder, and Fermented Ginkgo Biloba Powder. These products not only provide enhanced nutritional value and extended shelf life but also contribute to the creation of unique flavors and potential health benefits. Incorporating lactic acid bacteria fermentation into various food applications opens up a world of innovation and opportunity in the food industry.
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