China raised soybeans to the altars, more than 5,000 years ago, and Japan gave it a miracle category to keep its people healthy. The West also does not get rid of talking about longevity and today takes it as an essential substitute in the subsistence allowance without animal protein However, despite such a laureate biography, he still needs a trial that becomes increasingly punctilious. The last question, although not the final one, has been asked by a team of researchers from the Japan Public Health Center: is fermented or unfermented soybeans better?
Traditional oriental diets contain several types of soy products. Two of them are fermented with probiotics: natto, which is achieved with the bacteria Bacillus subtilis, and miso, with the fungus Aspergillus oryzae. Perhaps more popular are some of its unfermented versions such as tofu (soybean curd), and fried, the abura-age. The new study He has investigated the association between these types of soybeans and mortality in almost 100,000 Japanese people from different population areas, aged 45 to 74. The conclusions show a clear winner: while the intake of this unfermented legume is not associated with any cause of mortality, the fermented one – especially the natto – does have a clear protective effect against cardiovascular diseases.
An ally for the intestinal microbiota
Among the benefits that are added to soybeans through the fermentation process, according to other research, are the reduction of anti-nutritional factors such as protease inhibitors, that prevent protein digestion; phytates, which can prevent the absorption of minerals, and some oligosaccharides (sugars). “East food it could show higher protein content and less sugars, which can be transformed and generate short-chain fatty acids, some of which can be a nutrient for intestine cells, “explains Jaime Romero, a doctor in Microbiology and an associate professor at the Biotechnology Laboratory of Foods INTA, from the University of Chile.
Fermented soybeans seem to be liked by the small organisms that make up our microbiota: “Some bacteria — such as Bacillus subtilis which is used to make the natto – they are what we call probiotic. It also provides biomolecules such as spermidine, which promotes benefits at the cardiovascular level, “adds the expert. Eating it fermented also makes it easier to digest, says Juana María González Prada, dietitian-nutritionist and technical director of Alimmenta, who adds that this process increases the availability of predigested isoflavones, a type of flavonoids with antioxidant properties. Yes, The effects of intake depend on how each person metabolizes them.
A great nutritional source
As if that were not enough to be a big feast for the bacteria that inhabit the digestive system, the dietitian-nutritionist explains that this type of food “also provides other nutrients, such as fiber, calcium, iron, zinc, B vitamins and acid folic. They are free of cholesterol and their fats are mainly polyunsaturated. ” The quantity and quality of its proteins make it a great substitute for meat, although “it is somewhat deficient in methionine, which is solved by increasing the ration or by combining with cereals during the day,” continues the expert.
To introduce it into our diet, it is worth knowing what kind of products are on the market and, above all, Romero points out, look carefully at the labeling to know that we are consuming a quality product. “Attention should be paid to the type of fermentation and the ingredients used. Some use mixtures that may include rice or other foods. The nutritional value of the ferment should be represented by the balance between the protein component, the sugars and the fiber. “
Five options to get soy in your mouth
Miso “is also known as soybean paste. It is made from soybeans and cereals (rice, barley and wheat). They are added to a brine and subjected to fermentation by molds, yeasts and bacteria. It has a creamy color consistency that varies from pale yellow to reddish brown. Its salty aroma reminds of soy sauce. It is used as a condiment in soups, meat and fish stews, “explains González Prada.
The natto It is the result of bacterial fermentation of soy beans and cereal grains. It has a lower salt content and, according to González Prada, its fermentation causes the digestion of proteins, generating smaller proteins and amino acids. “They are pasty and mucous beans with a strong aroma and umami flavor,” says the expert.
Tamari It is made by fermentation of soy almost exclusively. “It is similar to soy sauce, its flavor differs in nuances and consistency. It is used as a condiment,” explains the specialist. One of the most popular is soy sauce, achieved by fungal fermentation followed by salting. “This dark brown liquid with umami flavor is used in many culinary preparations to flavor stews, soups, other soy derivatives and vegetables.”
The tempe it is made with “soy seeds that are washed and left to soak to favor fermentation lactic and a second fungal fermentation. The water is drained, inoculated with a previous manufacturing tempe or with a commercial inoculum and allowed to ferment. It comes in pressed blocks and is cooked. You can toast or marinate. “
Suffu is a product obtained from tofu, or curd of soy extract drink. “It is produced by fungal fermentation and subsequent salting, followed by ripening that lasts one or two months. It has the appearance of cured cheese.”
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