Consumers continue to demand healthier food products. Given the choice, most consumers would prefer to enhance or improve their diet using food and drink related products rather than pharmaceuticals.1
Soy ingredients are being used in food products by the food industry to enhance functional properties and to provide better nutrition.
Soybeans have great potential for use as human food because of their high level of good quality protein and their unique functional and nutritional properties. Soy protein supplies all nine essential amino acids and provides many functional benefits to the food processors. Most of the food industry uses soy ingredients in their products for a healthy image as well as for improving the product quality and managing cost.
Traditional soyfoods such as tofu, soy milk, miso and tempeh have been consumed for centuries by Asian populations. Adding these ingredients into mainstream food is not an easy process and sometimes taste becomes an issue. Instead of these products, the soy processors have come up with several soy ingredients such as soy flour, concentrates, isolates and textured soy protein that provide functional properties that have been widely embraced by the food industry.
One of the most important properties of soy protein in food systems is its ability to form gels after heating. Heat gelation contributes to textural properties, shapes the product, holds other food components and retains water in the product. Most functional soy protein ingredients are used to accomplish the following objectives: bind or immobilize fat and water;2 improve sensory or organoleptic properties; improve shelf life; regulate viscosity and modify gel structure. This information is essential for manufacturing and utilizing soy protein ingredients that will meet the food industry’s functionality requirements. From a sensory point of view, taste and color are the most important properties when using soy protein in food formulations, followed by texture and mouthfeel. Organoleptic properties include several variables, such as texture, fibrosity, juiciness, taste, flavor and color.
During the manufacturing of soy protein isolates, which by definition are at least 90% protein, unwanted flavors are removed. Sometimes, for certain applications, a flavor profile can be altered to accommodate specific needs. Research on flavor and taste continues to be important for future soy protein applications in food, since a small percentage of the flavor can carry through to the finished products (both in a positive and negative sense). The successful application of soy protein ingredients in the food industry requires they be capable of providing one or more key functional attributes at various critical stages in the fabrication, handling, storage, preparation and utilization of a given food product.
The food industry takes advantage of some of the functional properties including: adhesion, coagulation, color control, cohesion, colloidal stability, dispensability, elasticity, emulsification, fat absorption, flavor binding, foaming/aeration, gelation, hydration capacity, rehydration, solubility, viscosity, water absorption and binding.3 Additionally, soy can be applied as a fat substitute in items such as meat, fish, milk, cereal-based products and infant formulations. Food processors take advantages of these properties in different foods including, meat, sausages, baked goods, flour tortillas, desserts, pasta products, bread, simulated meats, whipped topping, desserts, cakes, beverages (dairy and non-dairy) soy drinks, soups, and gravies.4
The food industry uses soy ingredients to achieve specific functions. Examples of such uses include: soy flour, soy concentrates, and soy isolates are used in meat, sausages, baked goods, flour tortillas, desserts and pasta products where protein acts as adhesive material and provide adhesion. Full fat soy flour is used in bread and allied bakery products, where lipoxygenase enzymes bleach the flour and bakers control the color of their products. Soy isolates are used in meat and meat products, bakery items, to provide elasticity through disulfide links in gel deformable action. Textured soy protein and concentrate are used in meat and breakfast cereals. Soy fibers are used in beverages and other cereal based products and soy lecithin is used in the bakery industry.
References:
- Riaz, M. N. 2001. From soy processing to functional foods & nutraceuticals. “In Proceedings of Soy & Health 2000 Clinical Evidence, Dietetic Applications.” Eds: K.Descheemaeker & I. Debruyne; Garant Publishers, Leuven-Apeldoorn; pp. 37-45.
- Endres, J.G. Soy Protein Products: Characteristics, Nutritional Aspects, and Utilization, AOAC Press, Champaign, 2001, chap. 5, 6.
- Hettiarachchy, N. and U. Kalapathy. “Soybean Protein Products,” in Soybeans: Chemistry, Technology, and Utilization, Liu, K., Ed., Chapman & Hall, New York, 1997, chap. 8.
- Kinsella, J. E. 1979. Functional Properties of soy proteins. J. Am. Oil. Chem. Soc. 56(3):242-258.
Sidebar
Many Soy Ingredients Available for Food Applications
Currently, there are more than 20 different soybean ingredients that are available on the market for food application. These ingredients include:
- Roasted soy nuts
- Enzyme-active full-fat soy flour and grits
- Enzyme-inactive full-fat soy flour and grits, also called toasted full-fat soy flour and grits or heat-treated full-fat soy flour
- Extruder-processed full-fat soy flour and grits (enzyme-inactive)
- Enzyme-inactive low-fat soy flour or grits
- Enzyme-active defatted flake/soy flour (90 PDI)
- Defatted soy flake/flour with 70 PDI
- Defatted soy flake/flour with 20 PDI
- Soy flour (textured, refatted or lecithinated)
- Soy concentrates
- Textured soy concentrates
- Soy isolates
- Soy germ
- Soy isoflavones (mechanically extracted)
- Soy isoflavones (chemically extracted)
- Fiber from hulls
- Soy fiber from cotyledon
- Organic soy flour and organic concentrates