## 1 Introduction  
Soybean (_Glycine max_ L.) is an annual leguminous plant in the Fabaceae (_Leguminosae_) family that originated in the current area of the People's Republic of China (most likely the north and center) more than 3000 years ago, or even over 5000 years ago according to some reports [1; 2]. The overall dry matter composition of whole soybeans is approximately 40% protein, 21% lipid, 5% ash and 34% carbohydrate [3]. The limitation of its use in people's diets comes not only from isoflav but also from the produced flatulence, which is due to raffinose and stachyose. The digestive tract of humans does not secrete enzymes capable of hydrolyzation of the 1-4 galactosidic bonds in raffinose and stachyose to simpler sugars [4; 5]. Thus, they reach the area of the distal ileum and later the large intestine, where they are metabolized by bacteria and produce flatulence. About 90-95% of the protein is spare protein and has two subunits of storage proteins: 35% conglycinin (7S) and 52% glycinin (11S). The 11S fraction contains mainly legumin, and the 7S fraction contains vicillin and convicillin. Soy protein has a number of advantages over other types of natural proteins: increased biological value, low price compared to those of animal origin, non-animal origin and relatively long storage time due to stability [6; 7]. Soy protein is a macromolecule derived from plants of great interest in the biomedical field. Membranes, fibers, microparticles and even thermoplastics have also been developed based on soy protein in combination with other proteins (e.g., wheat gluten, casein), polysaccharides (e.g., cellulose, chitosan) and synthetic materials. The resulting materials are useful in tissue regeneration, wound healing and as targeted drug therapeutic systems [8]. In the past, soy protein was considered only as a traditional nutrient. In the second half of the 1970s, the hypocholesterolem effect of soy protein was discovered [9]. In addition, it decreases the expression of the lipogenic enzyme gene in the liver, according to a study in Wistar rats [10]. The protein from soybeans contains nutritious as well as useful components for the body, a series of anti-nutrients including protein-like substances such as trypsin inhibitors (which inhibit the digestion of food proteins and reduce their nutritional value by reducing absorption) and hemagglutinin (lectins that exert negative effects on the nutritional value of soy-based preparations and can usually be inactivated by heat processing) [11]. Goitrogens (substances that block the production of thyroid hormones by interfering with the uptake of iodine in the thyroid gland) are also part of the anti-nutritional category present in soy, which demonstrates the precautions that must be taken in the case of the preparation and consumption of soy-based foods in people with thyroid gland diseases, along with saponins and allergenic glycoproteins [12]. In the last three decades, numerous clinical studies have demonstrated the beneficial effect of soy consumption on plasma lipids in animals and humans. Introducing soy into the diet or even replacing animal protein with soy protein, according to research studies, improves the lipid profile in various animal species but also in men and women alike, especially in those with high levels of total cholesterol [13; 14; 15]. However, the mechanism of bioactive soy compounds responsible for this effect is not completely known, but of great interest are isoflavones. Soy dietary supplementation showed a decrease in the concentration of total and low-density lipoproteins (basically a decrease in LDL cholesterol), concomitant with an increase in high-density lipoprotein (HDL) cholesterol [16; 17]. Soy foods, due to their content of phytoestrogenic isoflavones, have been used to both decrease the risk of cardiovascular disease and to improve menopausal symptoms [18; 19; 20].