November 1, 2004
Imagine the following food offerings. First, a menu: celery stuffed with soy cheese, soybean croquettes, cocoa with soymilk, apple pie with a soy crust, and soy macaroons. Secondly, in the frozen food aisle, soy cream for whipping. Lastly, among the breakfast cereals, corn-soy cereal.
Though these might all sound like products offered in today's market, they provide an interesting glimpse of food history. The above menu was served in the Henry Ford Exhibit at the 1934 World's Fair. (Henry Ford was an early fan of soy.) The soy whipped cream was advertised in the May 1947 Family Circle magazine. Kellogg's advertised its new protein food -- Corn Soya cereal -- in the Feb. 19, 1951, issue of Life magazine.
It makes you wonder... Is there really anything new with soy? Thankfully, today's world of soy is just getting started.
Those who remember the beany flavor of earlier soy products can well imagine the difficulties of producing, much less selling, a soy dessert topping in the 1940s. But today, soy no longer tastes unpleasant. While flavor technology and masking capabilities have improved, so have the base products.
Soy continues to lose undesirable flavor, in part because of processing improvements. Kristen Heimerl, marketing manager, Cargill Health & Food Technologies, Wayzata, MN, credits the company's patented processing technology as one technique for producing clean-flavored soy isolates. "It's really a neutral flavor," she says.
According to Russ Egbert, director of protein research, ADM, Decatur, IL: "If you get back to the whole bean and soy varieties that are clean in flavor, you can actually get improved quality. The products that we produce from soymilk are much easier to flavor than an isolate base. There aren't as many off-notes that you have to try to mask. That comes down to selection of the right bean. The differences between beans are huge." Typically, commodity beans are processed into soy protein. However, specific varieties go into the production of soymilk or tofu.
For example, the L-Star hybrid soybean, produced by The American Soy and Tofu Corporation, Atlanta, has an exceptionally mild flavor. Through traditional breeding methods, Japan's National Agricultural Research Organization of the Ministry of Agriculture, Forestry and Fisheries developed this cultivar in 1990. Flavor and odor improvements come from removal of the three lipoxygenase isozymes, resulting in lower lipid dioxide in the processed soyfood. Soy flour produced from the L-Star soybean is comparable in flavor to wheat flour, though four times higher in protein. Additionally, L-Star provides higher protein and more vitamin E than most other U.S. and Asian soybean breeds.
Nowhere is flavor more important than in whole-bean products. As consumers look to less-processed foods in other sectors, such as in the return to whole grains, the soy industry is following suit. "What's new really, in some ways, is old," says Egbert. "We're looking at products that are processed less. The whole-bean area is going to continue to grow. We're moving back to more-basic foods. We're taking a look at soy as a whole and consuming the whole soybean instead of breaking it up into its constituent parts."
Whole-soy powder is produced from dehulled soybeans. Like whole grains, whole soy has high fiber levels, but it also is rich in isoflavones, phytosterols and soy protein. Whole-soy powders might undergo various processing steps, such as heat treatment or enzyme hydrolysis. Heat treatment will reduce the beany flavor. Enzyme hydrolysis enhances biological activity by converting insoluble fiber to soluble fiber, by hydrolyzing fats into functional polyunsaturated fatty acids, and by transforming dormant isoflavones into bioactive forms. Treatments increase shelf life and colloidal stability.
Soy beverages, frozen desserts, soy yogurt, soy cheese, soy ice cream and fermented-soy products can contain whole soy flour.
Egbert notes that organic and natural are both growing trends for the entire food industry, but with varying levels of demand around the world. "The demands for organic soy seem to increase," he finds. "We're seeing decreased interest in non-GMO products here in the United States." The reason? They cost more. While U.S. interest in non-GMO is waning, it is still of concern in other parts of the world.
Back to the basics
Just as the whole bean is becoming popular for its complete nourishing package, so are individual healthful components. Soy isoflavones are phytochemicals that offer specific biological effects. In fact, soybeans are the only food source that contains nutritionally significantly amounts of isoflavones.
Yet just because soybeans are rich in isoflavones, that doesn't mean all soy products contain them. Isoflavones can be lost during processing. Isoflavones aren't water soluble, and they can be washed away during alcohol extraction. Soy sauce and soy oil do not contain isoflavones. Depending on how it is processed, soy protein concentrate might or might not contain significant amounts of isoflavones. Alcohol-washed soy protein concentrates contain 5% to 20% the isoflavone content of water-washed concentrates. Typically, soy flour has a very high concentration followed by soymilk, tofu, tempeh and miso.
Soybeans contain two primary isoflavones: genistein and daidzein. A third isoflavone, glycitin is present in small amounts. Each of these isoflavones might occur in its beta-glycoside form. Additionally, an acetyl or malonyl group can attach at carbon six of any of the glycosides. Therefore, 12 different isoflavone isomers actually exist. The forms and amounts of each may vary in different soyfoods depending on the source of the beans and how they've been processed. Typically, genistein is found at higher levels in soyfoods than daidzein.
Just as flavor varies with soybean variety, so does isoflavone content. There can be as much as an eightfold variation in isoflavone content. In nature, isoflavones protect the soybeans from microorganisms, so isoflavone content increases when the plants are stressed from low moisture or other environmental factors.
A unique aspect of isoflavones is their chemical similarity to estrogen. Not surprisingly then, soy continues to make its mark in women's health. Research continues to uncover soy's role in improving menopausal symptoms and postmenopausal-health concerns, such as osteoporosis. Studies continue on the links between soy intake and breast-cancer risk, heart health, and thyroid function. Scientists are also discovering that soy can impact men's health, specifically by slowing the growth of prostate cancer. Prostate cancer occurs at similar rates around the world, but mortality is much lower in Asian countries where consumption of soy is high. Clinical studies are finding direct ties between isoflavones and the slowing of tumor growth. The same is true for colon cancer.
As soy's health attributes come to light and consumers look for ways to add soy to their diet, food manufacturers are looking at ways to increase levels of isoflavones in their products. Laurent Leduc, president, Acatris, Inc., Minneapolis, explains that base products, like soy flour, water-washed soy protein isolate and soy protein, provide modest amounts of isoflavones -- usually around 1.0 to 1.5 mg per gram of isoflavones. "It's not standardized," he says. "You never know if you're going to get 0.5 or 1.1 mg per gram."
Formulators can consider several options to bring higher levels of isoflavones into a food product. Acatris manufactures a product from soybean germ. "We have the 20 mg per gram, which is a 2% isoflavone made from the soybean germ," says Leduc. "It's a mechanical process to isolate the germ. We use soy germs because the plant naturally stores most of the isoflavone in the germ, but the germ is just a small percentage of the soybean seed. It takes about 400 lbs. of soybean seed to make 1 lb. of germ. But you get a product that is going to be 20 times more concentrated in isoflavones."
The soybean-germ product works well in breakfast cereals, bars, pasta and beverage powders. "Because it's a powder, it mixes very well with the other ingredients," says Leduc. "And because it is much more concentrated than the soy flour or soy protein, you need typically less than 2% of the total ingredients coming into the products.
"I think it is important to look at soy, not just from the isoflavones, but the whole package of nutrients that you find in soy," he continues. "When researchers are trying to isolate specific nutrients and study them, they sometimes don't find the health benefit as when you have the whole soy together. There is synergy between nutrients. Because we don't do any chemical process, in addition to the isoflavone, you still have 40% soy protein, 16% fatty acids, and it's loaded with other nutrients. It is very well possible that there is natural synergy between those nutrients, and if you try to isolate them and put them back together, you may have cut certain links that exist naturally between those nutrients. In the soy germ, there are about 40 different nutrients from the amino acids, the different fatty acids, the vitamins, minerals ... so there are a lot of nutrients here that exist in their natural form."
Processors chemically extract isoflavone extracts with either alcohol or ethanol. The extracts come in different concentrations, such as 10%, 20% and 40%. The dietary-supplement industry typically uses these ingredients because of their concentration and cost. They may be used in liquid beverages; however, solubility, flavor and clarity are usually issues of concern.
IntelliSoy, a new product produced by New Sun Nutrition, Carpinteria, CA, offers 100% clarity and solubility because it contains little to no insoluble fat, protein or ash. It contains upward of 70% soluble soy fiber and 8% to 20% isoflavones. Solubility is further enhanced by selection of glucoside and malonyl types, the most soluble of the isoflavone isomers. Although product designers can use the ingredient in a variety of applications, including baked goods, its unique solubility and clarity offer a solution to clear beverage applications.
The dairy industry is doing extensive research in separating proteins -- particularly whey proteins -- into specific peptides with certain functional and bioactive properties. Soy research is following the same path. "I can basically say that across all of the protein business, regardless of whether it's soy, wheat, milk, they are looking at all of those proteins for bioactive peptides," says Egbert. Soy might not be getting the attention of whey peptides, but nonetheless, the work is important.
At the University of Illinois, Urbana-Champaign, Elvira de Mejia, Ph.D., has identified soy peptides that lower blood pressure and cholesterol, others that might aid in preventing cancer, and even a satiety-causing peptide. While isoflavones might get the glory in some quarters, de Mejia believes that many of soy's health benefits are derived from its protein. "We have been producing and isolating from soybeans some peptides that have shown anticancer properties," she says. "Some are naturally present and some are produced by introducing different types of enzymes. The potential of soy protein is very, very huge to decrease some problems -- to prevent cancer, for instance."
One such peptide, lunasin, seems to inhibit malignant growth of prostate- and breast-cancer cells. In mice, it's effective against skin cancer. The intestine absorbs this peptide, making it available for the body's use.
Soybeans also contain a peptide called lectin. "There are reports in the literature about different types of lectin," de Mejia explains. "Some lectins prevent different types of cancer. Sometimes, lectins interact directly with the cancer cell and kill the cell. It depends on what type of cancer we are talking about and what type of lectin we are talking about. The biological activity of this protein changes depending on the source."
De Mejia's laboratory has identified different genotypes of the USDA collection at the University of Illinois, Urbana-Champaign. "We were able to identify genotypes with different levels of lunasin and also different levels of lectin," she said. "It is very interesting because we could suggest the possibility of producing the seed with a balanced composition of phytochemicals in soybean. We could balance the amounts of isoflavones, lunasin, lectin, saponins, and all the phytochemicals, and produce the perfect seed from a certain health standpoint.
"We know that soy products lower the risk of developing age-related chronic diseases, such as cancer and heart disease," de Mejia continues. "But we're still trying to understand what components in soy are responsible for its health benefits. This research is exciting because we're learning that bioactive peptides may be the reason soybeans are such a healthful food."
Any peanut lover who has traveled by plane recently has likely forgone their favorite snack for a package of pretzels. Those who suffer from peanut allergies sometimes can become symptomatic simply by inhaling airborne peanut allergens -- or even by touching objects handled by someone who has had peanuts in their hands.
Soy allergies might not grab the attention of airline travelers, but they do exist. People with this allergy can well attest to how ubiquitous soy is in food products. In addition to soy flour, protein and concentrate, lecithin is a commonly used food ingredient. Soy is often used in baby formula, and soy allergies are particularly common in infants and children. An allergic reaction to the soy P34 protein might be as mild as itching or, in rare cases, as severe as anaphylactic shock.
At last, a hypoallergenic soybean has been found. Ted Hymowitz, Ph.D., a plant geneticist at the University of Illinois, Urbana-Champaign, has searched for 20 years for this elusive soybean. After sifting through over 11,000 plant types, his laboratory found one confirmed P34-null line. Approximately 91 lines with significantly reduced levels of P34 have been found.
"The process we're using is looking for naturally occurring variants, so there's no question about the safety of it," he said. "We're providing an alternate approach to genetically engineering for a P34-null line. While there is no cause for concern in using biotechnology in baby food, people do worry and may not buy it."
According to de Mejia, while P34 is the main allergenic protein in soybeans, there are 20 others. Her laboratory has been analyzing commercially available soy protein products, including soy isolates, concentrates and textured soy protein. Many strategies can inhibit or denature this protein from food. "We are food scientists, so that's what we're trying to do," she says. "We are trying to find the conditions, temperature, pH, and presence of other components in the food that will favor the elimination of P34. We know now which commercial products have the highest or the lowest amounts of this allergenic protein." The scientists are trying to develop a method to inhibit the main protein responsible for allergenic responses so it will not represent any risk for the consumer.
Historically, soy's stronger flavor, high protein, and lower price made it an ideal complement to meat, albeit one that consumers initially looked upon as a cheapening of the product. Indeed, it was perhaps added initially as a meat stretcher, much the way flour was added to hamburger during the Depression. Yet as manufacturers improve soy products and their healthful qualities become well known, soy is a welcome addition -- if not a complete meat replacement.
Mian N. Riaz, Ph.D., head of the Extrusion Technology Program, Texas A&M University, College Station, sees advances in this category. For example, soy protein extracted from soy protein concentrate, is used to restructure a chicken breast. "The texture is very fibrous," says Riaz. "It's very similar to that chicken breast." High-moisture meat analogue is the newest development. He describes this as similar to fresh meat bought in the butcher shop.
Egbert explains that the technology might be new to us, but it was built in Japan nearly two decades ago. We're just applying it in the industry today. "This allows you to produce products that are more similar to intact meat and more similar to chicken breast than what some of the products on the shelves today are," he explains. They can be a stand-alone product, such as a package of precooked, diced and seasoned "chicken breast," or they could be used in as an ingredient by food manufactures and put into entrées. They are unique, because they contain 70% moisture.
What is the future of soy? "It really is something that can appeal to a broad audience," says Heimerl. "It isn't an ingredient that's a niche. It's something that we feel has capability to a very wide audience, and increasingly so as consumers become more and more aware of all of the health benefits. I think we'll see even greater customer awareness." She predicts soy will be accepted in more categories as studies continue to uncover all of its health benefits. Consumers have high awareness and acceptability of soy in certain areas, especially with regard to heart health and women's health.
"Here you have all these other benefits that soy protein is providing, but they aren't yet on consumers' radar screens," Heimerl continues. "Increasingly down the road, we're going to see it tap into other areas. We see gut health, or inner health, as really being an emerging area, so we're looking at it not just from a soy standpoint but from a broader standpoint, as well. That's definitely a growing area and something we're looking at particularly right now. We're looking at bakery and some other applications on that front. It's about bringing together multiple things to deliver the benefits."
Although some applications have proven themselves in select market segments, new opportunities exist for emerging consumer categories. "We're focusing on beverages and bars predominately, but we have just come out with some prototypes, a bakery blend for cookies, which is geared to the 'tween' segment," says Heimerl. "I think soy can play a role in kids' nutritional products, and that's an area that's emerging both in terms of bars and also as it relates to children, beverages too."
Other product categories that might have started based on a trend will likely continue in more of a generally healthy vein. "We see that the focus on being carb-conscious and the demand for products designed for weight loss featuring protein will likely continue to grow globally as obesity rates continue," says Geri Berdak, director, marketing communications, The Solae Company, St. Louis. "Specifically, we see that demand for products that offer satiety benefits and a low glycemic index will grow." In this regard, soy protein fits the bill because it's naturally satiating and offers a low glycemic index. She notes that "with soy protein, food manufacturers can support a structure/function claim relative to satiety: 'Soy protein can help you feel full, longer.'"
Laurent sees that with the introduction of IntelliSoy, beverage companies will be able to add isoflavones easily to liquid drinks. He asks: "Why not put some isoflavones in milk or in soymilk?" The milk industry should look at that, he suggests, because of the link between isoflavones and bone health. "I think there's quite a bit of synergy between calcium and isoflavones. You could easily target, for example, a dairy beverage for woman's health." For women going through menopause with osteoporosis concerns, such a product would pack a double punch. Adding a probiotic would even further enhance its healthfulness and marketability.
Riaz notes that soy is appearing in almost every food sector. "You have soy cookies and soy cereals," he says. "People are using it in different meat applications, dairy applications, beverages, smoothies. It's getting into all the bakery items and the cake mixes."
Indeed, it does seen as though soy is everywhere. Then again, 50 years ago, Henry Ford envisioned soy in everything from appetizers to desserts. Thankfully, it's quite a bit easier to develop and sell great-tasting soy products now than it was in 1934.
Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at [email protected] .
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