We’re in the thick of a four-part series on the basics of soy. The first article in this series focused on whole-soybean food products. In this second article, we’ll discuss ingredients made from soy that are used in many familiar foods.
What food ingredients are made from soy?
In the first article in our soy series, we talked about the nutritional components of whole soybeans and explained that soy is a mixture of carbohydrates, fat and protein along with nutrients like vitamins and minerals. Now we’re diving into food ingredients derived from soy, which are primarily made from the carbohydrate and protein parts of the soybean. These ingredients often are created by separating specific parts of the bean from its other components, a process that usually starts with removing the soybean oil (more on this process in our next article—stay tuned). When the oil has been separated from the other soybean components, what remains is a product that’s higher in protein and carbohydrates, including dietary fiber. Further processing steps create a wide range of soy-derived food ingredients that have many uses in our food supply.
Examples of food ingredients derived from soy:
- Soy flour Soy flour is made by milling soybeans. Soy flour can retain all of the naturally occurring fat of the soybean, or it can have some or all of the fat removed. Soy flours are used in products like baked goods; and, when mixed with water, they can serve as a vegan egg substitute in certain recipes. Flours made from soy are much higher in protein than wheat flours, but due to their lack of gluten and other differences in their nutrient content, soy flours usually can’t completely substitute for wheat flours in baking. Soy flour is a source of isoflavones, a class of polyphenols considered to have antioxidant properties. It also provides nutrients like iron, potassium and B vitamins.
- Soy protein isolate Soy protein isolate is what remains when the fat and carbohydrate portions of the soybean have been almost completely removed. These protein isolates are typically 90 to 95 percent protein and are a common ingredient in protein powders, infant formula, nutrition bars, plant-derived alternatives to meat, baked goods, breakfast cereals, some types of soymilk and other dairy alternatives. Unlike other plant-based protein sources, soy is considered a complete protein since it contains each of the essential amino acids our body needs for cell metabolism, tissue-building and repair, and energy production.
- Soy protein concentrate Removing the oil and some of the carbohydrates from a whole soybean leaves soy protein concentrate: a product that’s high in protein (about 70 percent) that also maintains the dietary fiber naturally found in soybeans. Soy protein concentrate is used in a variety of foods, including baked goods, cereals and some plant alternatives to animal meat.
- Soy fiber Soybeans are rich in dietary fiber in their whole-bean form, and this fiber can be extracted for use as a food ingredient. The extraction process can happen in a few different ways: soy fiber can be removed from soy protein through filtration when making soy protein isolate; it can be collected as a byproduct of making soymilk or tofu; and it can be made from grinding soybean hulls (this is typically called “soy bran”). Soy fiber can be found in foods like nutrition bars and beverages as well as baked goods, cereals and snack foods.
- Textured soy protein Also commonly labeled as “textured vegetable protein,” textured soy protein (TSP) is usually made from soy flour that’s had all of the soybean oil removed, leaving a high-protein food that’s used most often as a meat substitute. In addition to its high protein content, TSP is high in fiber and soy isoflavones.
- Soy lecithin Lecithin is a compound that is extracted from soybean oil and used as an emulsifier or stabilizer in many processed foods, including salad dressings, ice cream and other dairy products, infant formulas and breads.
Now that we’re familiar with whole soybean foods and food ingredients primarily based on soy’s protein and carbohydrate content, our next topic to tackle is soybean oil. We’ll fill you in on how the dietary fat found in soybeans is made and used in our food supply in the third article of our soy series.