Soy: Something New to Talk About
September 1, 2006
by BY REBECA LÓPEZ-GARCÍA, PH.D.
Is there anything new to talk about when it comes to soy? After all, soybeans (Glycine max) have been grown and used as human food for nearly 5,000 years. Their history as industrialized soy-based ingredients encompasses more than 40 years. Yet plenty of news continues to swirl about the topic of soy and the many ingredients derived from it.
Attitudes about Nutrition” sponsored by the United Soybean Board, three out of four American consumers say they have changed eating habits in the past three to five years because of health concerns. This study found 82% of the respondents rate soy products as healthy. Therefore, when a product is formulated to address the “healthy” trend, the use of soy-based ingredients immediately comes to mind.
This is only the beginning. Obviously the health trend is enough to spark new interest in soy, but there is more. The development of new processing technologies and the commercial availability of new-generation soybeans with unique characteristics have yielded
Soybeans have been officially connected to healthy eating since the Food and Drug Administration approved the soy heart health claim in 1999. However, it is only now that consumer attitudes have started to be significantly different. According to “2006 13th Annual National Report on Consumer soy-based ingredients with improved flavor, texture and functionality to offer the bakery industry diverse products and technological solutions.
Whole soybeans have 30% carbohydrates, 18% oil, 38% protein and 14% moisture, ash, vitamins and minerals. Other nutrients include phosphorus, potassium, B vitamins, zinc, iron, vitamin E and isoflavones, which are a class of compounds with estrogenic properties that contribute to soy’s association with promotion of hormonal balance.
In general, whole soybeans are dehulled then crushed to obtain the oil and soy flakes that contain protein, some fiber and the carbohydrate fraction of the bean. Grinding the flakes yields defatted soy flour (50% protein), and further processing gives soy protein concentrate (65% protein) and soy protein isolate (90% protein). Different technologies used for these processes and combinations of the final products with themselves and/or other ingredients have provided the industry with many new alternative ingredients for numerous applications.
SOYBEAN OILS TO THE RESCUE
The use of partially hydrogenated vegetable oils is widespread in the bakery industry because of their versatility in diverse formulations. However, trans fat substitution remains one of the major technological challenges for the industry, and new alternatives are needed.
Typically, soybean oil contains 61% polyunsaturated fatty acids composed of 54% linoleic and 7% linolenic, 24% monounsaturates composed of oleic acid and 15% saturated fatty acids composed of eliminate trans fats from a number of its food products. According to the press release, Kellogg’s will use a variety processed from Monsanto’s Visitive low-lin soybeans, as well as Bunge’s Nutrium low-lin soybean oils.
“Our goal is to make use of the most innovative ingredients possible and to encourage the accelerated production and adoption of low-lin oils so the public will benefit from this breakthrough technology,” said David Mackay, president and c.o.o. of Kellogg’s. “This is one of many steps we are taking to continue to provide healthy alternatives to consumers.”
While soybean oil remains the most flexible oil for bakery applications and is low in saturated fat content, low-lin soybean oil can replace most lightly hydrogenated soybean oils currently being used in bakery products. “In a few years, this enhanced oil will be joined in the marketplace by mid-oleic, low-lin soybean oil. This oil will couple greatly increased oxidative stability to the flavor stability of low-lin. It will be applicable to many bakery products that choose to not use the low-lin version,” predicted Mr. Galloway.
Another alternative for trans-fat substitution is the use of interesterified oils. Interesterification is generally achieved by blending fully hydrogenated oils (saturated fats) with nonhydrogenated oils (unsaturated oils) to achieve specific melting profiles associated with various functional attributes. It rearranges the fatty acids in soybean oil to allow the blend to function like the partially hydrogenated oils it replaces. Because partial hydrogenation is not involved, trans fats are not created in the interesterification process, and the taste, texture and flavor of foods is maintained. The interesterification process can be achieved either chemically or enzymatically. Interesterified soybean oils are semi-solid at room temperature and work best in applications where a solid or semi-solid 11% palmitic and 4% stearic. Although the relatively low level of saturated fatty acids is a positive aspect from a health standpoint, the high amount of polyunsaturates leaves soybean oil susceptible to instability. The presence of linolenic acid, a known omega-3 fatty acid, is desirable for its potential health benefits, but the presence of three carbon-to-carbon double bonds makes linolenic acid unstable and susceptible to oxidation reactions and production of, among other things, off flavors.
According to Richard Galloway, president of Galloway & Associates LLC, Isle of Palms, SC, and a consultant to Qualisoy, St. Louis, MO, a collaborative program of the US soybean industry, one of the most notable recent contributions to the food industry is low-linolenic (low-lin) soybean oil. Mr. Galloway defined it as “a vegetable oil that has increased flavor stability without hydrogenation” and stated that “it is suitable for use in biscuits and crackers and as a coating oil for crackers and cookies.”
Because low-lin soybean oil does not have the flavor stability problems of conventional soybean oil, it should provide flavor enhancement and needed shelf life to bakery products made with this oil, while also providing a no-trans answer to formulators. In fact, Kellogg Company, Battle Creek, MI, announced in early December 2005 that it would reformulate using Qualisoy-approved, low-lin soybean oil in an effort to “fat” is used such as in formulating margarines, spreads and shortenings and in confections and baked goods where they contribute to the texture, mouth feel, structure and aeration of the end product.
SOY WORLD The FDA-approved soy health claim requires 6.25 g of soy protein per serving. Trying to take advantage of this claim, the baking industry is constantly on the search for ingredients that will help enhance the soy protein content of its products while balancing the cost. According to Mian Riaz, Ph.D., director, Food Protein R&D Center, Texas A&M, College Station, TX, speaking for the United Soybean Board, “Using soy protein is the only way a bread can reach the amount of soy needed for the soy heart health claim.”
Deborah Schulz, market development manager, Cargill Foods, Minneapolis, MN, stated that “usually, product developers are going to be adding a soy protein to provide a nutritional benefit, whether it is simply for the protein nutrition or it is for the health benefits of the soy.” However, nowadays, it is also important to consider the cost. “If a more expensive ingredient is going to be added, it has to bring something to the right market,” Ms. Schulz continued.
There is a wide variety of soy protein products available to the baker. These vary in the protein content and balance of other soybean components such as protein, fiber and fats. “Typical Commercial Uses of Soy Flour Products” (Page 110) summarizes these. The baking industry has used soy flour because of its good performance in a variety of products and the additional fiber benefit.
An innovative soy flour ingredient is how Terry Gieske, business development director, Kerry Ingredients – Nutriant Soy Ingredients, Cedar Falls, IA, described functional soy powder (FSP), which is a unique balance of protein, fiber and trans-free fat. She observed, “In cake systems, FSP can be used to replace significant portions and even all of nonfat dry milk and eggs. In cookies, FSP can be used with liquid vegetable oil to deliver characteristics that currently require hydrogenated fats or palm oil. Egg replacement with soy flour is an important factor in cost reduction.”
Ms. Gieske stated that by using FSP with cake systems, the baker gets cost management, processing ease, excellent freeze-thaw tolerance and extended shelf life. With cookies, FSP delivers the option for a healthier position at a lower cost than most palm oil solutions.
According to Ann Stark, applications manager, Cargill, the use of relecithinated (15%) 70 PDI soy flour in bakery products such as pancakes, cookies and muffins yields products with acceptable appearance, flavor, aroma and texture profile and with significant cost savings. In addition, soy flour is used in cake donut formulations at 1 to 3% to increase the moisture of the finished donut and decrease the fat retained after frying. Addition of soy flour increases the ability of the finished product to hold the added water in the formulation, thus contributing to the overall donut quality and increasing the yield from a fixed amount of dry ingredients. When soy flour is used in this type of formulation, the fat up-take during frying is reduced. Inclusion of approximately 2% on a dry basis of 70 PDI soy flour can decrease the final content of fat after frying from 21 to 19%. Savings to the donut manufacturer arise from the lower cost of the fat repulsion ingredient and from the reduced loss of fat from the fryer. The ultimate winner is the consumer who enjoys a donut that is less greasy in appearance and somewhat lower in calories.
Cost reduction can also be achieved through soy’s tremendous ability to absorb water and control moisture migration, thus lengthening shelf life and improving batch yield. “For example, a 1% (flour weight basis) addition of soy flour will increase finished moisture levels by 0.3 to 0.5%; therefore, yield goes up,” explained Ms. Stark.
Ms. Schulz added, “Isolates have not been used as much but are now being looked at to add more protein to several products.” With higher protein concentration and less carbohydrates, isolates have fewer off flavors and can be used in sensitive products such as white breads. However, soy isolates can be difficult in leavened dough environments, so blends of soy isolates and soy flour are more commonly used to give better functionality. Isolates have also been used as ingredients for frostings to speed drying because of their hygroscopic power. This has helped some companies that are trying to meet the criteria for the health claim by adding soy protein wherever they can, according to Ms. Schulz. However, justifying the increased cost remains a challenge.
Soy flours are also used for formulation of protein bars. Supro 313/Supro 320 isolated soy proteins from The Solae Co., St. Louis, MO, are specifically designed to extend the shelf life of nutrition bars, prevent bar hardening and target specific bar textures. Jean Heggie, Solae’s marketing director for North America, said in a recent interview with Baking & Snack that this group of ingredients offers precise ratios to achieve textures across the board, from very chewy to more cookie-like. The range of new applications make protein bars more appealing to the consumer in general.
“People want to feel better about snacking,” stated Ms. Stark. This opens a brand new market for different soy products and applications. Recently, Cargill developed a prototype pretzel that contains enough soy protein and nonsoy fiber to make a “good source” claim for protein in a snack product.
Kerry Ingredients recently introduced Nutriant’s all-natural dryroasted soynuts. The soybean flavor is removed during processing, resulting in a bland yet roasted flavor. These products are available plain, salted or with tropical coatings. Ms. Grieske stated that “unique new technology enables Kerry to infuse flavor into and throughout the soynut.” Soynuts have a positive impact on cost, nutrition panels and “healthy indulgent” marketing positions. They are less costly than tree nuts and eliminate nut issues such as shells, allergens and mycotoxins. These products can be used as a nut replacement or as a nut extender and can be infused with allergen-free nut flavors. In addition, soynuts are significantly lower in calories with less than half the fat of typical nuts.
According to Ms. Schulz, addition of texturized soy flour adds a “crunch” to different products such as granola, protein bars and other snack products. ProSante textured soy flour crisps are a complete source of protein with the economy of a textured vegetable protein. The crisps are prepared by processing soy flour through an extruder to give an expanded, porous structure. Textured soy flour has a protein content of 54% (with a fat content of 1% or less) and is available in different shapes (flakes, mince and chunks).
Cargill developed two prototype health bars that contain more than 30% textured soy flour by weight. These bars meet FDA’s health claim for foods containing soy protein. In addition to being healthy, these snack bars are a tasty, portable and convenient way to consume soy protein. In addition, Cargill has developed soy snacks for hard-core chocoholics. These products are unlikely to qualify for a health claim but contain substantial amounts of soy protein at 3.1 g per 40-g serving in the cranberry crunch soy chocolate variety and 2.6 g protein per 40-g serving in the moist, chewy filling of a chocolate covered almond candy style. Healthful and delicious, who could ask for more?