Prepared by
Katherine Cason, PhD, RD
Clemson University

Soy oil accounts for 79% of the edible fats and oils used annually in the United States.

Table of Contents for Phytochemicals Introduction Food Guide Pyramid What are Phytochemicals? How Do Phytochemicals Work? Where Can You Find Phytochemicals? Soy Foods What are Some Soy Foods? Can I just take a phytochemical pill? How can I get more phytochemicals in my diet? Summary Review questions Back to Nutrition Curriculum Lessons

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What are Some Soy Foods?

Soybeans and soy products, such as soybean oil, soy flour and soy protein, are used extensively in a variety of foods found in a typical supermarket. Soy beverages, tofu, textured soy protein and soy flour can be used as foods or incorporated into many dishes, baked goods and other foods. The soybean and its components give foods sound nutrition, good taste, a long shelf-life and a competitive price. Many of the products available are listed below.

Soy oil accounts for 79% of the edible fats and oils used annually in the United States. Soybean oil contains 61% polyunsaturated and 24% monounsaturated fatty acids, totaling 85% unsaturated fatty acids. Soybean oil is particularly rich in linoleic and linolenic fatty acids. Soybean oil is a chief component of mayonnaise, margarine, salad dressing and vegetable shortening.

Soy flours are the simplest form of soy protein. The flour is produced by grinding and screening defatted soy flakes. Soy flour is about 50% protein. Soy flour can be found in baked goods, noodles, cereals, pancake flour, frozen desserts and instant milk drinks.

Soy isolates are developed through a chemical process in which most of the protein is withdrawn from the defatted flake. The resulting product contains about 90% protein and very little moisture. Soy isolates are the chief component of many dairy-like products, including processed cheese, soymilk, infant formula, non-dairy frozen desserts and coffee whiteners. They are used to add texture to meat products and are valued for their emulsifying properties.

Soy concentrates contain about 65% protein and retain most of the bean's dietary fiber. Concentrates also add texture and help foods retain moisture. Surimi, protein drinks, soup bases and gravies contain soy concentrates.

Soybeans, especially the outer hull, are an excellent source of dietary fiber (six grams fiber per one cup cooked). When soybeans are processed, the hull is removed and then processed further to create a fiber additive for breads, cereals and snacks. Soybeans contain both soluble and insoluble fiber. Soluble fiber may help lower serum cholesterol and control blood sugar. Insoluble fiber increases stool bulk, may prevent colon cancer and can help relieve symptoms of some digestive disorders.

Whole soybean foods such as full fat flour is made from whole soybeans and therefore has the same fat, protein and dietary fiber content as the whole bean. Full fat flour is used for doughnut mixes, pie crusts, pancake batters and other baked goods.

Soymilk is made from ground soybeans that are mixed with water to form a milk-like liquid. It is consumed by dairy-sensitive individuals as well as strict vegetarians who eat no animal proteins. Soymilk is an excellent source of protein, B-vitamins and iron, and, if fortified, provides adequate calcium. It has low levels of saturated fat and no cholesterol.

Textured soy protein (known commonly as TSP or TVP) is made from defatted soy flour which is compressed and dehydrated into a product rich in protein and fiber, low in fat and sodium. TSP is used as a meat enhancer, extender and substitute.

Mainstays of healthy diets throughout the East for centuries, Asian whole soybean foods are slowly gaining acceptance in the United States as a unique source of nutrition that can help reduce saturated fat in the diet. Whole soybean foods are high in protein, fiber and unsaturated fat, and rich in vitamins and minerals. They also show many anticarcinogenic properties related to the unique benefits of soy isoflavones.

Tofu (soybean curd) is a bland, cheese-like cake formed from soymilk by adding a coagulant (typically calcium sulfate) to the milk to form curds that are then shaped and pressed into cakes. Depending on the coagulant used, tofu is rich in minerals and is an excellent source of high-quality protein, polyunsaturated fats (including linoleic and linolenic acids), B vitamins and iron. Versatile and nutritious, tofu can be used in soups, salads, pastries, sandwiches and spreads. It can also be used as an alternative to yogurt or soft cheese.

Miso is a thick, high-protein paste made from soybeans, salt and a fermenting agent (usually an Aspergillus mold culture) that is similar in taste and color to soy sauce. Sometimes a grain, such as rice and barley, is fermented with the soybeans for additional flavor. Miso is popular as a soup and breakfast drink in Japan. The fermenting yeast in miso makes it a rich source of vitamin B-12. In addition, research has shown that antioxidant components in miso may inhibit formation of oxidized cholesterol that forms plaque in the arteries (Santiago et al., 1992).

Natto is made of fermented, cooked whole soybeans and offers nutritional values similar to those found in miso. It has a sticky, viscous coating and is strong-smelling, with a cheesy texture. It is used as a spread or in soups.

Tempeh is made of whole, cooked soybeans infused with a culture to form a dense, chewy cake. It is a good source of fiber protein, polyunsaturated fats and lecithin, as well as useful amounts of calcium, iron, magnesium, potassium and some B vitamins.

Soybean sprouts are rich in vitamins A, B and C and are eaten raw in salads or cooked.

Soy sauce, the most widely recognized of soybean foods, is fermented from a mixture of whole soybeans, wheat flour and fermenting agents, such as yeast, for about 18 months. Then the liquid is extracted and processed. Soy sauce adds sodium and flavor to the diet.