Soy Protein Benefits
Soy Protein Benefits : For the human body, protein is an important nutrient. They are the main building blocks of our body tissue and can also act as a fuel source. Likewise fuel, proteins provide energy into our body. Protein is an essential nutrient that our body utilizes to create new enzymes, muscle tissue, and hormones. Really, protein exists in every cell in the human body, it means that to work properly our body needs to get plenty of protein through our diet. Every protein molecule is consists of amino acids, which is the building blocks that are concatenated together on chains to form protein. When evaluating a protein powder product contents, the amino acid is one of the most important factors. There are total 22 types of amino acids used by the human body; in which 9 of these cannot be synthesized by the body and must be obtained from dietary sources. Soy protein is “complete” protein, it means that it contains these nine essential amino acids. After digestion of dietary protein, our body rearranges these amino acids to build a structure of new protein required to perform numerous physiological processes.
Since 1959 soy protein isolate has been used in foods for its functional properties. Now, due to its use in health food products, soy protein popularity has increased, and many nations allow health claims for foods rich in soy protein.
Drinking protein shakes is one of the best ways to get enough protein in our diet. There are different varieties of protein powder available in the market, each with its own advantages and disadvantages. The most general form of protein is soy protein.
Soybeans are a variety of legume they have high protein content while remaining are comparatively low in fat. To make soy protein, manufacturers grind soybeans into a meal which contains no hulls or fat. Then this soybean meal is processed into isolate of soy protein, which consists of 90 to 95% only protein (Soy foods Association of America, 2013). Then this soy protein isolate is available in powder form. Although natural soy protein isolate is high in protein but very low in carbohydrates, to improve its taste, texture, and nutritional value many manufacturers add additional nutrients to commercial soy protein.
Table of contents :
- Use of soy protein isolate by consumers
- Industrial use of soy protein isolate
- Nutritional and health benefits of soy protein isolate
- Use of soy protein concentrate
- Quality requirements
- Aqueous alcohol wash process
- Acid-wash process
- Water removal process with heat denaturation
Soy Protein Benefits
- Soy Protein and Heart Disease
- Soy Protein and Osteoporosis
- Soy Protein and Abdominal Body Fat
- Soy Protein and Cancer Risk
The bottom line
Product types –
Soy protein has a strong nutty flavor and has a texture a bit grainier. Dehulled and defatted soybeans are processed into three types of high protein commercial products: soy flour, concentrates, and isolates.
Soy protein isolate is a well refined or purified form of soy protein. It has 90% protein content on a moisture-free basis. From defatted soy flour, it is made, from which most of the non protein components, fats, and carbohydrates are removed. It has a natural flavor and will cause less flatulence than soy flours due to this.
Primarily Soy isolates are used to develop the texture of meat products but are also helpful to increase protein content, and as an emulsifier to enhance moisture retention.
Mainly pure form of soy protein isolate is utilized by the food industry. Sometimes we find it in health stores or in the pharmacy section of the supermarket. Usually, it is found combined with other food ingredients.
Use of soy protein isolate by consumers
Soy protein isolate can be used in numerous ways. It can be added to juice, milkshakes or smoothies, or it can be sprinkled on cereal to enhance the protein content of the food. Homemade soy yogurt, which is normally too watery, can be made thicker by adding some soy protein isolate. The thickness of yogurt is because of the clotting of proteins in an acid environment.
Industrial use of soy protein isolate
Soy protein isolate can be utilized in the food industry for nutritional (increasing protein content), sensorial (better mouthfeel, flavorless) and functional reasons (for applications needed for emulsification, water, and fat absorption and gum type characteristics).
Soy protein isolate is utilized in the following food products :
- meal replacements
- breakfast cereals
- energy and protein bars
- weight loss ready-to-drink beverages
- soups, sauces and prepared foods
- baked foods
- ice cream, yogurt, likewise many dairy or dairy-free products
- meat alternatives
- processed meat, poultry, and fish products
Nutritional and health benefits of soy protein isolate
Soy protein isolate is a complete source of vegetable protein. It contains all basic amino acids for growth and it is similar protein as in meat, milk, and eggs. On the other hand, it’s fat content is very low. Soy protein isolates decrease the risk of coronary heart disease. Also, there are signed that soy protein can help in the avoidance of osteoporosis, some cancers and menopausal symptoms. Soy protein isolate has fewer health benefits than soy protein concentrates or whole soybeans. During the production of soy protein isolate the protein is washed away with alcohol, removing most of the isoflavones. The isoflavones have many health benefits, for example, improving arterial vasodilatation, lowering cholesterol and preventing from atherosclerosis.
Soy protein concentrate is nearly about 70% of soy protein and is normally defatted soy flour without the water-soluble carbohydrates. From removing part of the carbohydrates (soluble sugars) from dehulled and defatted soybeans it is created.
Soy protein concentrate contains most of the fiber contents of the original soybean. It is broadly utilized as a functional or nutritional element in a wide variety of food products, primarily in baked food items, breakfast cereals, and in some meat products. Soy protein concentrate is used in meat and poultry products to enhance water and fat retention and to develop nutritional values (more protein, less fat).
Soy protein concentrates are available in various forms: granules, flour, and spray-dried. Due to their digestible property, they are very much useful for children, pregnant and lactating women, and elderly people. We can also utilize it as pet foods, milk replacements for babies (human and livestock), and even used for some nonfood applications.
Use of soy protein concentrate
In a wide variety of food products, such as in baked foods, breakfast cereals and in some meat products, soy protein concentrate is widely utilized as a functional or nutritional ingredient. Soy protein concentrate is utilized in meat and poultry products to boost water and fat retention, and to develop nutritional values (more protein, less fat). It is even utilized for some non-food applications.
On a moisture free basis, soy protein concentrate contains at least 70% protein. Depending on the extraction method, the protein can have various solubility properties. Some applications, such as drinks, need a highly soluble protein. The soy protein concentrate made with the alcohol wash will have low solubility which can be incremented by further processing, such as by neutralization of acid washed concentrate with alkali. Soy protein concentrate can be found in numerous forms: granules, flour, and spray dried. Most of the properties beany flavor is normally removed by the extraction process, resulting in tasteless end products. The flatus-producing sugars raffinose and stachyose can also be removed by the solvents utilized in the production of soy protein concentrates.
By grinding soybeans into a fine powder soy flour is made. Normally it comes in three forms: whole or full-fat (contains natural oils); defatted (oils removed) with 50% protein content and with either high water solubility or low water solubility; and lecithinated (lecithin added). Because soy flour is gluten-free, yeast-raised breads made with soy flour are dense in texture.
Generally, Soy protein is made from dehulled, defatted soybean meal. By clearing away most of the soluble non-protein compounds the concentration of protein is achieved. Mainly these compounds are soluble carbohydrates and some nitrogenous substances and minerals. Because of this process, much the undesirable beany flavour and oligocharides (raffinose and stachyose) are cleared away. Soy protein concentrates is tasteless.
There are three techniques to produce soy protein :
- Aqueous alcohol wash process
- Acid wash process
- Water wash process with heat denaturation
By utilizing these techniques soy protein concentrate will yield with similar composition: 70 percent protein, 20 percent carbohydrates, 6 percent ash and about 1 percent oil. The solubility of the protein can vary between the various extraction processes. One ton of defatted soybean flakes will provide nearly about 750 kg (75 percent yield) of soybean protein concentrate.
Aqueous alcohol wash process
In this process, the sugars are dissolved with alcohols (methanol, ethanol or isopropyl alcohol) in a bunch or a continuous process. These alcohols can not dissolve the soy proteins. Defatted soy flakes are utilized as raw material. The alcohol is recovered and re-used after the extraction of the sugars. This recovery is completed by evaporation and rectification in a distillation column. The remaining flakes are dried with hot air and milled.
When the pH level is nearly about 4.2., the soybean protein becomes insoluble in water. With this low pH, it dissolves the sugar without the use of special solvents. This procedure is safe because of the absence of flammable solvents. But, it is more difficult to remove the water from the soy protein. Most of the water is evacuated with rotary vacuum filters or centrifuges to obtain solids wet milled and spray dried.
Water removal process with heat denaturation
The soy proteins of defatted soy meal are first accomplished insoluble by thermal denaturation with this process. The meal is heat treated first and then extracted with hot water to remove the sugars. The procedure is the same to the acid-wash procedure.
Soy Protein Benefits
Soy protein is a very healthy product: it contains very low fat, cholesterol free and phytochemicals. The primary phytochemicals in soy protein are isoflavones, saponins, and phytic acid. These phytochemicals are solid antioxidants but have many other characteristics. Soy protein and its connected phytochemicals seem to decrease heart disease, osteoporosis, and cancer risk.
Soy Protein and Heart Disease
Soy protein decreases the cholesterol and helps to decrease the risk of heart disease. The most relevant scientific investigation about the relationship of intake of soy protein and heart disease is the meta-study by Anderson et al (Meta-analysis of the effects of soy protein intake on serum lipids. N Engl J Med 1995;333:276-282). They came to a conclusion that the intake of soy protein rather than animal protein really decreased serum concentrations of total cholesterol, LDL cholesterol, and triglycerides without really affecting concentrations of serum HDL cholesterol.
In an investigation, Anthony MS et al found that isoflavones in soy protein increase cardiovascular disease risk factors without probable harmful effects on the reproductive system of peripubertal rhesus monkeys (Soybean isoflavones increase cardiovascular risk factors without affecting the reproductive system of peripubertal rhesus monkeys. Journal of Nutrition 1996;126:43-50).
In this investigation Erdman, J.W et all recommend that (Soy protein and cardiovascular disease: A statement for healthcare professionals from the nutrition committee of the AHA. Circulation 2000;102(20):2555-9) that incorporating soy protein in a diet low in saturated fat and cholesterol advances heart health. They accepted that the daily consumption of more than 25 g soy protein, with its related isoflavones, could increase lipid profiles in hypercholesterolemic humans. They also accepted that in preventing heart disease soy protein without the isoflavones affects less . Taking supplements of isoflavones without soy protein does not lower cholesterol but may give many other cardiovascular benefits.
An investigation published in the Journal of Nutrition studied the effect of soy compared with dairy protein on the gut bacteria of hamsters to decide whether changes in gut bacteria could account for lipid-lowering characteristics of soy protein. Serum total and LDL-cholesterol concentrations were effective in the group fed with soy protein concentrate. The analysis comes to a conclusion that the type of protein affected gut bacteria and that soy protein may decrease lipogenesis through alterations of the gut bacteria.
Soy Protein and Osteoporosis
Investigation gives a suggestion that consuming soy protein and the replacement of animal protein with plant protein may protect against osteoporosis. Maybe women of Japan have less calcium intake than most Western women do they have a lower prevalence of fractures. This could be exaggerated by the soy protein consumption of Japanese women. Alekel, D.L. et al found that soy isoflavones weaken loss of bone from the lumbar spine in perimenopausal women.
Soy Protein and Abdominal Body Fat
A question comes to mind that soy protein contains calories, near about 4 kcal per g, but does its consumption increase our body fat? Definitely, if you add extra soy protein to your diet you may expect the increase of your weight. One investigation studied the effect of a supplementation of soy protein daily or dairy protein on body fat of postmenopausal women. The scientists found that the team who consumed soy protein lost abdominal fat (-12 ml), whereas the team who had the soy protein replaced with dairy protein (casein) showed an increase in abdominal fat (+39 ml). Other factors, such as total body fat, insulin secretion, and lean mass did not vary between the teams. This investigation came to a conclusion that a daily supplementation of soy protein prevents the increment in subcutaneous and abdominal fat, observed with an isocaloric casein placebo in postmenopausal women.
Soy Protein and Cancer Risk
Epidemiological investigations advocate that soy protein may decrease the risk of certain cancers, along with breast cancer and prostate cancer. Women from Japan, who eat a large quantity of soy protein (mainly from soy tofu and miso), have a much lower risk of breast cancer or prostate cancer than Western people. The anti-cancer effect of soy protein could be explained by the phytochemicals, which are connected with the soy protein. These phytochemicals incorporate the isoflavones (genistein, daidzein, and glycitein), phytic acid and saponins. Isoflavones and phytic acid have solid antioxidant characteristics and can avoid oxidative damage by free radical to our DNA and cells. Shu X.O. et all give a suggestion that high consumption of soy during adolescence may decrease the risk of breast cancer in later life (Soyfood Intake during Adolescence and Subsequent Risk of Breast Cancer among Chinese Women. Cancer Epid Biomarkers Prev. 10: 483-488). Conversely, the association between consumption of soy protein and decreases risk of breast cancer was observed for each group of soyfoods examined.
An investigation by Mercer et al studied the effect of soy protein in mice that were treated with diethylnitrosamine and ethanol. As expected the ethanol incremented the occurrence and variety of basophilic lesions and adenomas. Soy protein really decreased progression of adenoma and decreased liver injury. The scientists came to a conclusion that soy avoids tumorigenesis by decreasing pro-inflammatory and oxidative environment resulting from an ethanol-induced liver injury.
The bottom line
For all these reasons soy protein is normally called as the storage protein held in discrete particles called protein bodies which are estimated to contain at least 60-70% of the total soybean protein.