Soybeans have been grown as a commercial crop in the US since 1920. They provide a rich source of vegetable protein, called soy protein, and are used to make soy fiber and soy flour. Soy flour contains approximately 50 percent protein and soy protein is 90 percent protein. The fat content of soy flour and soy protein is very low. Soy flour is about 34 percent carbohydrate, while soy protein contains no carbohydrates.
Traditionally, soy protein has been used as a substitute for animal protein. It is used in baby formulas, medical nutrition products, as a protein supplement, and in bakery products.
Soy protein concentrate is used in hot dogs, sausages and bologna, and it is used as an extender in frozen dinners, pizza toppings, tacos, meat spreads and poultry products. It is used because of its ability to absorb water and fat. Tofu is an example of soy protein that can be made from soy flour. It is a protein curd that is made by precipitating the protein from soy milk, and has a texture similar to cottage cheese.
Many types of soy fiber products are used in liquid diet formulas in hospitals, low-calorie breads, and baked goods.
Soy fiber is 75 percent dietary fiber, 12 percent protein and less than 0.2 percent fat. Soy fiber contains both soluble and insoluble fiber, and has been shown to lower blood levels of cholesterol and to improve bowel function. Also, studies have shown that soy fiber may help control blood sugar in patients with diabetes. Soy fiber is one of the best fiber supplements available.
Your best source of fiber
If your daily fiber intake is not enough, you may need to increase your intake. Good sources of fiber include:
- Whole Grain Products
- Soybean, peas and other legumes
- Nuts and Seeds
Refined or processed foods are low in fiber, such as canned fruits and vegetables, pulp-free juices, white bread and pasta, and non-whole grains. The grain refining process removes the husk (bran) of the grain, which reduces the fiber content. Fortified foods are processed to add some B vitamins and iron, but not fiber.