Black soy - The functional properties of soy benefit the health of its consumers

Everyone knows common soybeans, whose grains are beige in color. But, in fact, there are types of soybeans of different colors and shapes and also with very specific characteristics. In 2019, Embrapa, in partnership with EPAMIG and Fundação Triângulo, launched a black soybean cultivar known as BRSMG 715A. The primary objective of developing this cultivar was to offer an alternative to expand the adoption of soybeans in human consumption, maintaining its productive potential in agriculture.

There are several characteristics that differentiate black soybeans from commercial cultivars, in addition to color. The first of these is the higher protein content, which makes it more nutritious. The second is the ease of cooking. The third is the pleasant taste, according to the tests carried out. The fourth is the greater proportion of monounsaturated fatty acids, which gives them greater oxidative stability. And the fifth is that it is rich in anthocyanins (which give the black color), which are natural antioxidants. The fact that this cultivar was developed with black color was not by chance, since the underlying strategy is to use it as a partial or total substitute for black beans in the very Brazilian feijoada.

In the first year of cultivation, the objective was to produce seeds for new crops, while studying the market. The most promising so far is that of the East, especially South Korea, which has shown interest, due to the ancient habits of Asian people in using soy in food production, combined with the functional food characteristics of this soy cultivar.

Black soy and its benefits

The consumption of black soybeans is common in Asia, where it is consumed as a healthy food and used in folk medicine for centuries, being rich in proteins, lipids, minerals and isoflavones. However, what sets it apart are the black pigments in the seed coat, made up of polyphenols such as anthocyanidins and flavonoids, which contribute to the antioxidant capacity of black soybeans. A study demonstrated that consumption of black soy (35% of the diet) for 10 weeks in ovariectomized rats increased antioxidant activity, inhibiting oxidative stress and improving lipid profiles, resulting in the reduction of risk factors associated with cardiovascular diseases. (CVD). This article can be accessed at http://bitly.ws/qz8z. Another study with guinea pigs demonstrated that the oral administration of black soy extract in rats, at 50 and 100 mg/kg of body weight, for 14 days, reduced the risk of CVD by improving blood circulation through the inhibition of platelet aggregation and thrombus formation (http://bitly.ws/qz8I).

Functional food and its benefits

Functional foods are those that, in addition to providing nutrition, produce beneficial effects on health, especially in reducing the risk of chronic degenerative diseases, especially diabetes and various types of cancer. Black soybeans are one of them.

Part of the benefits come from ingredients with antioxidant capacity, which have the ability to protect cells against the effects of free radicals produced by the body. The antioxidant serves to donate electrons, either to free radicals or to cells affected by them, reducing or eliminating oxidative stress produced by free radicals

Vascular function is closely related to the risk of CVDs. One of the risk factors, perhaps the most important, is the aging of the organism, which causes functional and structural changes to the vascular wall. Increased vascular stiffness is the main consequence, and compromises vascular adaptation to changes in blood flow and blood pressure.              

In addition to aging, oxidative stress is another important trigger of vascular dysfunction, especially because it is enhanced by the aging process. Scientific research has already demonstrated that the change in the content of nitrogen oxides, such as nitric oxide (NO), is a preponderant molecular event for vascular function, as the release of NO from endothelial cells reduces the concentration of calcium inside the cells , causing relaxation of vascular smooth muscle, being considered a potential vasodilator. It turns out that both aging and oxidative stress significantly reduce NO production and can lead to vascular dysfunction.

Vascular dysfunction and harmful stimuli - such as oxidative stress - are closely related to CVD risk. This is where the importance of polyphenols contained in foods comes into play, which reduce the risk of its occurrence. Black soybeans are rich in polyphenols, including isoflavones, anthocyanins, anthocyanidins, and flavonoids, and their preventive effects on CVD risk have been reported in several animal experiments, as previously reported.

Benefits for human health

There are also scientific studies conducted with human populations. In one of the studies, carried out in South Korea, it was reported that supplementation with black soybean extract (2,5 g / day), for 8 weeks, decreased the accumulation of visceral fat and plasma lipid profiles in adults with excess fat. Weight (http://bitly.ws/qz8Z). Other research was conducted by the group of Dr. Yoko Yamashita of Kobe University (http://bitly.ws/qz7n). In this study, scientists investigated the effect of black soy consumption on vascular function and oxidative stress, associated with polyphenol concentrations in healthy women. Decreased vascular age was observed in 33 of the 44 volunteers who completed the 8-week study. An improvement in vascular stiffness was observed, increasing the level of NO2 and NO3 in urinary secretion, and decreasing oxidative stress markers. For those who like chemistry, the markers used were 8-hydroxy-2'-deoxyguanosine, hexanoyl-lysine and myeloperoxidase.

The study also showed that the concentration of 12 polyphenols, present in black soybeans, increased in the plasma and urine of the test population, as a direct function of the consumption of black soybeans. The conclusion of the study was that consumption of black soy improved vascular function, through an increase in nitric oxide and a decrease in oxidative stress, accompanied by an increase in polyphenol concentrations in healthy women.

It is no coincidence that the studies above were carried out in South Korea and Japan because, as we mentioned previously, there is an ancient habit of using soy in human nutrition in the East. This is a reason that also leads South Korea to propose importing black soybeans from Brazil.

But, what about us Brazilians, who have developed and are able to produce black soybeans, won't we benefit from the benefits it provides? It is time for public policies and campaigns by private organizations to be developed so that the population of our country effectively benefits from a new, nutritious food option with health benefits.