Characteristics of Soy Protein Concentrate (SPC) The general composition
of SPC made by three processes is shown in the table. The most obvious difference is that the ash content in SPCs prepared by acid extraction or hot water extraction is lower, indicating that minerals are removed more thoroughly. About 5% to 10% of the carbohydrates remaining in the SPC after leaching are soluble sugars, and the rest are insoluble polysaccharides. The amino acid composition of SF, ethanol or acid-extracted SPCs and ethanol-extracted soybean solubles is shown in Table 19.6. Among the essential amino acids, phenylalanine, tryptophan, methionine and cystine are concentrated in the soluble part of soybeans during the alcohol extraction process.
| Element | Alcohol washing | Pickling | Hot water washing |
|---|---|---|---|
| Protein (N × 6.25) b | 71.0 | 70.0 | 72.0 |
| protein | 67.0 | 66.0 | 68.0 |
| Moisture | 6.0 | 6.0 | 5.0 |
| fat | 0.3 | 0.3 | 0.1 |
| Crude fiber | 3.5 | 3.4 | 3.8 |
| Ash | 5.6 | 4.8 | 3.0 |
| Carbohydrate c | 17.6 | 19.5 | 20.1 |
- a
- The data is expressed as a percentage.
- b
- Dry solid basis; all other data are presented "as is".
- c
- The percentage difference.
SPC is provided in powder (95% to US No. 100) or granules (US No. 60 retention rate is 90%) as well as fat or lecithin. Typical bulk density: 0.40~0.45 g/cm3 (25 to 28 lb/ft3) for powders, 0.54 to 0.61 g/cm3 (34~38 lb/ft3) for granules, and 0.43 to 0.48 g/cm3 (27 to 30 lb/ft 3) for 9% lecithin products.
According to USDA-FNS requirements (Table 19.7), SPC, SPI, and organized SF and SPC must be added with vitamins and minerals to meet the requirements of some meat or meat substitutes in domestic school lunches and child nutrition programs. There are separate strengthening requirements for military ground beef applications (PP-B-2120B).
| Vitamins and minerals | Minimum/g protein |
|---|---|
| Vitamin A, International Unit | 13.00 |
| Thiamine, mg | 0.02 |
| Riboflavin, mg | 0.01 |
| Niacin, mg | 0.30 |
| Pantothenic acid, mg | 0.04 |
| Vitamin B6, mg | 0.02 |
| Vitamin B12, micrograms | 0.10 |
| Iron, milligrams | 0.15 |
| Magnesium, mg | 1.15 |
| Zinc, mg | 0.50 |
| Copper, microgram | 24.00 |
| Potassium, mg | 17.00 |
Cereal products and their processing
By providing the functional performance and sensory qualities required by manufacturers and consumers, soy protein concentrates and isolates are important food ingredients in many processed food systems. They also provide nutritionally balanced, relatively low-cost, and high-quality protein, which can be used alone or in combination with other protein sources. New technologies for removing the undesirable color and taste of soybeans have been reported, and soy protein-based products with improved organoleptic quality can be developed even in the case of high-level use. Various physical and chemical processes, such as extrusion and partial proteolysis, have changed the function of soy protein. And greatly expand their application in new foods.
As consumers' awareness of the relationship between diet and health continues to increase, as well as the nutritional advantages of soy protein products such as low calories, high fiber, and low saturated fat, the demand for soy protein products will increase. However, it should be noted that the expansion of the utilization rate of soy protein products and the successful establishment of the soy protein industry also depend on the viable market for other main ingredients, in the case of soybeans, it is mainly oil. Although soybeans have to compete with many oilseeds in the vegetable oil market, soybean protein faces much less competition from other plant sources (including oilseeds and starch crops), mainly due to its mature market and advanced technology.
Development of new foods based on phytonutrients
Compared with other protein sources, soy protein concentrate has higher nutritional value, is cheaper, and has more functions in food. Recent studies have shown that consumption of soy protein can help reduce total serum cholesterol and reduce risk factors related to various cancers, which has changed consumers' attitudes towards soy protein (Drake et al., 2000). Because of its high-quality protein content, soy foods mainly attract vegetarians. In addition, soy foods are an important source of omega-3 (n -3) fatty acids. However, a lot of research has been conducted on the potential health effects of soy foods without considering their nutritional content (Messina, 2014). Soy foods are a rich source of phytoestrogens, although they are also found in a range of other foods. Research on phytoestrogens has reported risk-related factors, including osteoporosis, heart disease, breast cancer, and menopausal symptoms. They are also specifically mentioned as endocrine disruptors because they may cause adverse health effects (Patisaul and Jefferson, 2010)). Research mainly involves soy products and their phytochemicals, especially isoflavones. Isoflavones are phytoestrogens or plant hormones. Genistein and daidzein are essential isoflavones in soybeans, and their structure is similar to estrogen. Therefore, isoflavones occupy some of the receptor binding sites of estrogen, resulting in reduced estrogen effects, and may promote the growth and spread of cancer .