In terms of fortification, soy protein long has been a major ingredient in packaged food, beverages and supplements. People have been eating soybeans for nearly 5,000 years. The first soy ingredients were soy flours, the primary applications of which were bread and other bakery products in the United States in the 1940s. Since then, because of their excellent functional and nutritional characteristics, use of soy in baking has steadily increased — even intensified — especially after the U.S. Food and Drug Administration’s (FDA) 1999 approval of a health claim based on the association between consumption of soy protein and a reduced risk of coronary heart diseases.
Soy offers numerous health claims and trends look promising for this functional ingredient.
Focusing on functionality
Functional properties of proteins can be defined as the physicochemical properties and their interactions with other food components. These properties are not only important in determining the quality of the final product but also in facilitating processing such as the improved machinability of cookie dough.
Other benefits include moisture retention during baking, improved cake tenderness, crumb structure and texture, enhanced rate of crust color development, and extended shelf life. Soy also functions similarly to nonfat dry milk in bread and rolls, at about half the cost. To use soy ingredients effectively, formulators should have detailed information on methods of preparation and processing, as these affect the composition and functional properties of the component proteins.
Soy may be divided into four classes: Soy ingredients, traditional soy foods, second-generation soy foods and foods where soy is used as functional ingredient. Soy ingredients include raw (or unprocessed) soybeans, soy flours (defatted and full fat), soy concentrates, soy isolates, texturized vegetable soy protein and hydrolyzed soy protein. Foods where soy is used as a functional ingredient include baked goods in which soy flour is added.
With its unique nutritional and functional properties, soy has found wide application in bakery products.
Claims with soy
Research has found that soy protein, when included in a low-fat and low-cholesterol diet, could lower total cholesterol and low-density lipoprotein or “bad” cholesterol levels without adversely affecting high-density lipoprotein or “good” cholesterol levels.
The claim states that 25 grams of soy protein per day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. The FDA claim recommends consumers incorporate four servings of at least 6.25 grams of soy protein into their daily diet, for a total of at least 25 grams each day. This has significantly increased the demand for soy in the food industry, including the baking industry.
According to Soyfoods Association of North America, 12 other countries make similar statements on soy protein, including Japan, South Africa, The Philippines, Brazil, Indonesia, Korea, Turkey, Malaysia, Chile, Colombia, India and Canada.
Soy protein is also said to help the maintenance or achievement of a normal body weight, maintenance of normal blood cholesterol concentrations and protection of DNA proteins and lipids from oxidative damage. However, in 2012, the European Food Safety Authority published a scientific opinion concluding that a cause-and-effect relationship was not established between the consumption of soy protein and those health claims.
Soy ingredient market
Soy ingredients, including flours, grits, protein concentrates, protein isolates, textured soy protein, soybeans and germs, have found an array of applications in bakery products.
Cargill offers Prolia soy flour, which contains 50% protein. Because it is a complete protein — meaning it contains all essential amino acids at the levels required — soy protein is a popular choice for bakers wanting to create high-protein products, said Amanda Donohue-Hansen, business development manager, Cargill. Soy flour is often used to increase protein in baked foods by replacing a certain percentage of flour.
“Soy flour does bring different functionality, particularly water-holding capacity, as compared to wheat flour,” Donohue-Hansen said. “As a result, the balance of other ingredients must be carefully managed so as not to adversely affect texture, flavor or shelf-life.”
To offer complete nutritional value, the blending of different plant proteins is a new trend. Donohue-Hansen said the company offers a blend of both pea and soy protein. Pea protein tends to have less water-binding capacity compared to soy. While pea protein contains all the essential amino acids, it is not a complete protein because two of the amino acids, methionine and cysteine, are limiting: The two combined are present at less than 25 mg per 1 gram of crude protein. Soy, on the other hand, contains all of the essential amino acids at the appropriate levels.
“By using the two ingredients together, in just the right ratio, formulators can take advantage of the functional benefits of pea protein yet still make complete protein claims,” Donohue-Hansen said.
CHS, Inc. offers Honeysoy defatted soy flour and grits for bakery applications. The company claims that with soy flour at 50% protein, functional benefits include increased water binding, which increases yield along with longer shelf life. Other potential uses for soy flour include tapping into the growing vegan, vegetarian and gluten-free markets.
Soy in the future
The baking industry seems cautiously optimistic about the future of soy flour. Euromonitor International identified soy protein as an option to meet the demand for high-protein bread.
In its “Ingredients in Bread: Fresh Recipes for a Stale Industry” report published in May, Euromonitor identified soy protein as an ingredient widely used to fortify products. According to the report, however, concerns over GMOs and soy’s allergen status have deterred some consumers. Sources such as pea, rice and potato allow manufacturers to avoid soy and continue pushing the high-protein angle.
Demand for plant proteins continues to grow. Soy proteins offer versatile functionality, a complete nutritional profile and are among the most cost-friendly proteins on the market, noted Donohue-Hansen. There are many different soy ingredients that vary in their chemical composition and functional properties. Prior to selecting any soy ingredient, the characteristics of a finished baked good should be carefully evaluated.
Further improvements in raw material and ingredient functionality coupled with innovative food processing technologies will enable bakers to introduce a variety of new, more economic and better-for-you products.
Editor’s note: Dr. M. Hikmet Boyacioglu is a former consultant for American Soybean Association-International Marketing, ASA-IM and US Soybean Export Council.