Adding Soy Ingredients for Health

Adding Soy Ingredients for Health

By Cindy Hazen
Contributing Editor

Early in my career at a seasoning house, the technologists had to sample pilot-plant products. While we were accustomed to tasting various soy-containing meat items, the products created for export to Mexico brought the loudest groans: Mexican regulations allowed higher levels of soy, and that meant more off-flavors.

At the time, we added soy because it was inexpensive. It was an efficient way to extend meat. For American consumers, adding soy was a means to a more-economical product.

How perceptions have changed in just two decades! Not only has soy-product quality improved, but research is uncovering numerous health benefits associated with soy consumption. Greg Paul, Ph.D., director, nutrition strategy, The Solae Company, St. Louis, says research over the last 30 years has shown a positive role for soy protein in areas such as bone health, menopausal-symptom relief, cancer-risk reduction and heart health. FDA’s 1999 heart-health claim for low-fat foods containing 6.25 grams of soy protein per serving has not only boosted consumer awareness, but also demand for soy products in a variety of categories.

According to the 11th annual survey, the 2004–05 “Consumer Attitudes About Nutrition Study” sponsored by the United Soybean Board, Chesterfield, MO, 74% of U.S. consumers perceive soy products as healthy. Out of 1,000 random consumers, 44% of females and 28% of males stated that soy might provide a healthy addition to their diet. And because of this, 27% of the consumers seek out products that specifically contain soy. Of those surveyed, 39% were aware of specific health benefits of including soy in their diet, and 29% were aware that soy is good for the heart.

Product designers have many ingredients at their disposal. The industry can meet the challenge of incorporating soy into a broad spectrum of foods by using soy flour, soy protein concentrate, soy protein isolate, isoflavones and soymilk.

Soy in a nutshell

What makes soy healthy? Whole soybeans contain 30% carbohydrates, 18% oil and 38% protein. The carbohydrate portion includes 15% dietary fiber. The oil is 85% monounsaturated. Soy protein is the only plant-based protein that contains all essential amino acids in the proper proportion for human health; each carries the highest protein digestibility corrected amino acid score of 1.0. Additionally, all soy products contain important nutrients such as phosphorous, potassium, B vitamins, zinc, iron, vitamin E and phytochemicals, including isoflavones.

Soy is the only major food source of isoflavones, a class of compounds with estrogenic properties attributed to improving hormone balance and prostate health. Researchers at The University of Texas M. D. Anderson Cancer Center, may even have uncovered a link between isoflavone consumption and lung cancer. In one study, those who ate the highest amount of foods with these phytoestrogens had a 46% reduced risk of developing lung cancer, versus those who ate the lowest quantity.

Actual nutritional content depends on the ingredient and its processing. Basic soy processing dehulls the soybean and then crushes it to extract the oil. This leaves soy flakes, which contain the protein, some fiber and the carbohydrate fraction of the bean. Simply put, grinding the flakes gives defatted soy flour (50% protein), or the flakes may be further processed into soy protein concentrate (65% protein) or soy protein isolate (90% protein). Processors might separate the protein with a chemical process, basically acid precipitation, or by membrane filtration. Full-fat soy flour (40% fat) is also available, made from beans from which the oil has not been extracted.

Soymilk is made from dehulled, crushed beans. Processors add water to make a slurry and heat the product. Once they remove the fibrous okara, “you end up with a liquid soymilk at a concentration somewhere around 12% to 14% soy solids,” says Kate Leavitt, director international sales and marketing, Sunrich, a SunOpta Company, Hope, MN.

“The industry had to go into full gear to really study what’s going on to make certain flavor compounds and bring sensory sciences in line with the ingredient business of soy,” says Bob Rasmus, sales director, wellness and innovation,ADM Specialty Food Ingredients, Decatur, IL. “One of them is lipoxygenase. I would focus on a couple of sugars, too, which are the oligosaccharides raffinose and stachyose. It’s not something we have a palate for.” The higher levels of oligosaccharides can produce some off-flavors. “On the positive side, though,” he continues, “oligosaccharides are dietary fiber.” Soy flour and soy concentrate contain more fiber, or nonsoluble sugars, than soy protein isolate.

Soy has a high level of sulfur-containing amino acids. However, Paul suggests soy protein is lower in sulfur-containing amino acids than other common protein sources. “The kidney does not have to work as hard in its role to excrete waste products and maintain the body’s acid/base balance,” he says. “What separates soy protein from other proteins is that soy protein is easier on the kidneys and is associated with a drop in blood cholesterol when consumed as part of a reduced-calorie diet.”

Although isoflavones are abundant in the whole soybean, subjecting ingredients to certain processes might remove them: Concentrates are often processed with alcohol, a step that strips out the isoflavones. The “USDA-Iowa State University Database on the Isoflavone Content of Foods—1999” reports that water-washed concentrates contain about 102 mg total isoflavones per 100 grams concentrate compared to 12 mg total isoflavones per 100 grams alcohol-extracted concentrate.

When planning a nutritional claim, the ingredient must contain nutrient levels sufficient to meet that claim when used at the level that provides a palatable product. “Most of the time, the reason people are going to be adding a soy protein is to provide a nutritional benefit, whether it is simply the protein nutrition or whether it’s for the health benefits of the soy,” says Deborah Schulz, market development manager, Cargill Foods, Minneapolis. Once the designer decides on the target protein level, he must address functionality. In a beverage, for example, “the food formulator needs to look at things such as viscosity, solubility, suspension stability over time and how well it tolerates the processing to achieve that suspension,” she says. “Something that’s going to be retorted might require different functional properties than something that is going to be pasteurized and sold refrigerated.” Like all food-formulation challenges, ingredient knowledge is key.

Flour power

Soy flour shines in snack and baked-goods applications. “The addition of flour not only gives you fiber for the ingredient declaration,” advises Rasmus, “it also, quite frankly, processes easier than an isolate. With an isolate, you’re dealing with strictly protein—and ash, or minerals. When that’s all you have to work with, sometimes it’s pretty hard to machine.” Processing can enhance the functionality of the flour. “You can either make it hydrophyllic or hydrophobic,” he says. “In some food applications where you don’t want a lot of water activity, you have to shut down those natural processes.”

One new product, referred to as “functional soy powder” by Terry Gieske, business development manager, Kerry Ingredients, Nutriant Soy Ingredients, Cedar Falls, IA, acts much differently than a traditional flour, concentrate or isolate. “We’re using it in bakery applications to replace milk and egg,” she says. “In things like pancake mix, for example, you can take out all the milk and all the egg and have comparable volume, cell structure, performance and sensory characteristics.”

When paired with a polyunsaturated liquid vegetable oil, the functional soy powder can replace hydrogenated fats in cookies. “You can have zero trans and less than a half of gram of saturated fat in a 28-gram cookie that tastes and looks just like the hydrogenated- fat version,” says Gieske. “Not only have you removed the arteryclogging fats, you are adding soy protein.” She says a recent study funded by the National Heart, Lung, and Blood Institute found low-density lipoproteins decreased in women taking soy protein, regardless of age, race, other lipoproteins, dietary saturated-fat intake and weight.

One common product using soy might surprise the health conscious. Who would have thought to look for soy in a fried donut? “The soy protein, when it comes in contact with the heat in that process, will denature, and it will form a barrier for the rest of the dough so that the oil doesn’t penetrate, and you don’t end up with a soggy product,” Rasmus says. It adds protein, and that brings color through heat processing, as well as some structure.

Rasmus notes it is sometimes necessary to add a more-concentrated form of soy protein—a concentrate or isolate— when formulating for nutritional benefits. “Usually, if we see someone moving to an isolate or a concentrate, it’s because they’ve got a protein target that they want to deliver,” he says.

Though a fried donut with its high fat content wouldn’t qualify for a heart-health claim, some consumers might view the addition of soy as boosting the overall nutritional benefit. Other baked goods or snacks, depending on the process and formulation, might meet the FDA-required 6.25 grams of protein per serving for a label claim.

Choosing concentrates and isolates

“Protein makes up about 90% of soy protein isolates and 65% of soy protein concentrates,” says Paul. “Soy protein offers weight-management benefits via protein effects on satiety. People feel full longer and eat fewer calories when protein like soy protein is added to the diet. Soy protein also appears to be responsible for the cholesterol- lowering effect. Earlier research suggested a role for the isoflavones in conjunction with the protein. Even though such a combination may exert a slightly greater effect than soy protein alone, current research suggests that the protein is most important.”

Leavitt concurs. “We can say that the FDA health claim on soy, as well as the U.K. health claim on soy, is attached specifically to soy protein. It’s not separated out on isoflavone level or some other component, because there has been scientific indication that the benefits of soy come best when it is in a whole-soy product.”

As soy is processed to concentrate protein, fiber and some isoflavones will be lost. Yet flavor will improve due to removal of some oligosaccharides. Many isolates have neutral flavors.

Soy concentrates and soy isolates are not pull-off-the-shelf products because of their functional attributes. Manufacturers custom-tailor products to work within specific product parameters, and technology provides new options for soy.

Tofu aside, consumers who want to increase soy consumption generally reach for a beverage or nutrition bar. “Though people are looking at moving into other areas, beverages and bars are still the primary categories,” says Pam Stauffer, marketing programs manager, Cargill Foods.

One area where soy is gaining in popularity is low-pH beverages. Because of their higher isoelectric point, whey protein has dominated. “Soy has always had a little bit of a functional disadvantage compared to whey. Soy is not soluble at an acidic pH, where whey is,” says Rasmus. “There are a couple of ways to address that. The soy can be bound-up with another ingredient that will keep it soluble across a greater range of pH.” Texturant systems are another approach. “There is going to be some kind of texturant system in the beverage for mouth-feel,” he says. “You have to find how the texturant system and the protein can work together so that you can keep that protein in solution while it is on the shelf.”

An acid-stable protein has been specifically designed by Nutriant for beverages at or below pH 3.8 “to stay in suspension without requiring gums or pectins,” says Gieske. “It has a light, clean mouth-feel, so you can go anywhere from a mouth-feel like apple juice, all the way through to the creamier, smoothie kind of consistency. The beverages will still have the opacity that is typical of soy and can have an excellent range of mouth-feels, levels of protein inclusion and pH stability.”

Nutrition bars have also benefited from new technology. Formerly, formulators would pack isolates and/or concentrates into the core to give bars a protein punch. “Now, with the changes in technology, you can put the protein into virtually every component within the system,” says Gieske. “You can find it in the caramel filling, in the soft nougat center and in the chocolate compound coating on the outside. You can make much more familiar-tasting products because you can spread the soy inclusion out across the whole system rather than putting it in just one thing.”

Adding soy protein to chocolate bars might be one way to enter the kids’ market. “We’re seeing increasing interest in adding soy protein to nutrition bars, beverages and cereals that are specifically targeting kids and addressing their unique nutritional needs,” says Jean Heggie, marketing leader, The Solae Company. “Certainly, the benefits of getting healthful, high-quality protein into kids’ diets, particularly at breakfast and at snack time, is certain to be an area of increasing market interest— particularly as it might relate to satiety and improved mental focus and performance. The satiety benefits are relevant for kids in school. Kids have been shown to perform better academically when they are not hungry. Thus, by helping kids to feel full longer, including soy protein at breakfast and lunch may help them perform better in school.”

Soy crisps add 60% to 80% protein and give nutrition bars crunch and a better bite. “We’ve seen interest from the baking area to provide a crunch,” says Schulz. “It could be used in a cereal in and of itself. You could put it into a granola. Or you could season it on its own and make a snack. We also had some creative people looking at putting a ranch seasoning on them and using them as a crunchy salad topper.”

Identifying isoflavones

While soy protein consumption has been linked to satiety and weight-management benefits, soy isoflavones are associated with hormonal balance.

The two well-known isoflavones are genistein and daidzein. Others occur in soy and probably play a role in the bean’s benefits. “Glycitein was discovered in the last 5 to 10 years, so it is not talked about as much,” says Jocelyn Mathern, R.D., technical specialist, Acatris, Inc., Minneapolis. Soy contains 12 different isomers, because each of these three isoflavones may manifest as a beta-glycoside, and an acetyl or malonyl group can attach to any of the glyocides at carbon six.

An active area of soy isoflavone research is equol production. This metabolite of daidzein is an isoflavone, says Mathern, “but is formed only from the breakdown of daidzein after you eat soy. Apparently, only a certain part, one-third to one-half of the population, can actually produce this compound.” Research indicates people who can produce equol experience more health benefits from soy. Equol exhibits stronger estrogenic activity than daidzein.

“All isoflavones are estrogenic,” Mathern says. “Isoflavones have a chemical structure that is similar to human estrogen, so they can attach to estrogen receptor sites.” Isoflavones are weaker than human estrogen. For women low in estrogen, such as those in menopause, the isoflavones can attach to receptors and help boost those levels. “But for women who have too much estrogen and for people where it is a concern, the isoflavones can actually block the estrogen and attach and have a weaker estrogenic effect than the actual estrogen,” she suggests.

The effects of soy isoflavones have engendered some medical controversy, because some studies conclude high isoflavone levels might increase breast-cancer risk. Other data suggests that, under some conditions, soy isoflavones might help prevent breast cancer.

Mathern believes, and most of the health community concurs, that the concern centers on isoflavone supplements as opposed to consuming a serving of food. For example, 1 cup of soymilk contains about 20 mg of isoflavones. “Most people are trying to get up to that range of 20 to 50 mg,” she says. That is the benchmark of the Asian diet.

Recently, Japan’s Cabinet Office’s Food Safety Commission agreed a daily supplement intake of 30 mg of isoflavone is safe. Adding soy consumed in food, the Commission capped daily isoflavone consumption at 75 mg, but noted that exceeding the upper limit would not cause immediate health damage. Adding isoflavone ingredients to foods might provide consistent levels. Soybeans are nonstandardized for isoflavone content. “You can’t guarantee a certain level of isoflavones,” says Mathern. “Soybeans will contain 0.1% to 0.2% isoflavones.”

As for the isoflavones that naturally occur in the soybean, says Rasmus, “depending on the process, you can either remove them and concentrate them and then offer them separately, or you can leave them intact in the product and deliver it in an isolate.” He notes isoflavone levels vary depending on the soybean variety and growing conditions.

Acatris offers a soy germ that is standardized to contain 2% isoflavones. “All we do is remove the germ from the soybean mechanically and then mill it,” says Mathern. “It is natural. We blend the beans, so we blend different germs from different areas to make sure that there’s always 2%.” This is important when a nutrition label specifies isoflavone content, she notes, so “every time you can guarantee you’re getting the same amount.”

This soy germ comes in three different milling sizes, from a granule to a 60- to 80-mesh fine powder. “Our most popular is the consistency of soy flour,” Mathern says. “It can go in a lot of different products. The most-popular applications are breakfast cereals, waffles, bagels, pizza crusts and nutrition bars.” The inclusion rate is low, 1% to 2% of the formula, and she says it provides a “kind of a nutty flavor.”

Soymilk solutions

Leavitt sees an interesting correlation between American soymilk and those found in Europe or Asia: “Around 90% of the soymilk in the United States is either certified-organic or made with organic soybeans. It has some organic claim. You don’t necessarily see that in other countries. I think it is a byproduct of soymilk being originally introduced in the health-food market.”

Soymilk is produced from whole beans. “We differentiate that from soy protein isolates or soy protein concentrates that may be chemically extracted,” says Leavitt. Mechanical extraction also produces a cleaner flavor. Nutriant, it should be noted, expeller-presses its soybeans.

Applications for liquid or powdered soymilk include beverages, smoothies, cultured soy, frozen desserts, puddings, non-dairy creamers, and sauces and gravies. Spray-dried soymilk sometimes substitutes 1-to-1 for skim- or whole-milk powder. It can range from 54% to 26% protein and 16% to 50% fat. Spraydried soymilk has a shelf life of 18 months. Liquid soymilk can contain 54% to 45% protein and 16% to 24% fat on a dry-solids basis.

Soy and juice combinations are popular in Spain. For processing, Leavitt notes, “you have to have certain types of equipment to help offset protein precipitation.” She advises using high-pressure homogenizers. Similarly, coffee’s acidity can create protein separation. “We have specifically manufactured soymilks that are best suited for coffee applications,” says Leavitt.

“In Europe, we’re seeing more work in soy non-dairy applications such as soy desserts, soy puddings and cultured-soy products like yogurt-type products,” continues Leavitt. “What I find quite interesting is it’s not all in the low-fat, super-healthy category. It seems to be often geared toward taste. A rather-indulgent, perhaps a rich-and-creamy soy pudding or a frozen soy dessert isn’t trying to make a low-fat claim. It’s just saying, ‘Hey, I’m great tasting. I’m indulgent. I’m delicious. I happen to be made with soy.’”

In the end, that’s probably the best way to bring soy’s healthful benefits to consumers. Many Americans want to eat nutritious foods. They want to be healthy. But they also want indulgence. “The days of the soy burgers that tasted like hockey pucks is not where we’re going to grow this business,” Leavitt laughs.

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].

Studying the Soy Consumer

It all started with a simple little bean. Few would have thought it would have such a major impact on the food and beverage industries, creating new products and offering healthier alternatives to traditional favorites. Of course, we are talking about the soybean.

Soy protein is low in saturated fat and cholesterol. In 1999, FDA approved a soy protein health claim stating that eating 25 grams of soy protein a day might help reduce the risk of heart disease. The benefits of soy have been told and heard. Who’s listening? Everyone. Who’s buying? Well, that’s a different story.

Soy attracts two distinct sets of people: consumers who use soy products on a regular basis and those who want to, but are leery. They want healthful alternatives to have flavor and texture profiles as close to mainstream products as possible. In other words, make mine “soy healthy,” but don’t make me compromise.

How does a product developer reach this group of educated but leery consumers? Slowly. Such a major conversion can’t be made overnight. A highly successful enterprise incorporating soy into traditional favorites has been seen in smoothie shops. People are replacing their standard caffeinated drink with a healthier smoothie made with soymilk or flavored with soy powder and are willing to pay premium prices.

Soy has made its way into the school lunchroom. Schools include soy protein in meat-based entrées, helping meet dietary guidelines by lowering fat content per total calories. In a survey of more than 10,000 students, over half rated soy-enriched meats as very good in taste tests, and over two-thirds said they’d eat soy-enriched products again. They’re also reaching for flavored soymilks. This is a generation worth paying attention to.

The praises of soy have also reached women over 40. Soy-foods are often rich in isoflavones, which might help decrease menopausal symptoms. Soy protein has been successfully incorporated into meat alternatives such as burgers, franks, sausages, yogurts, cheese and frozen treats. Soy flour can be used in baking recipes for muffins, cakes and breads. A little soy and a little imagination can go a long way in creating the next generation of soy enthusiasts.

—Michele Reisner, Howard Moskowitz,
Moskowitz Jacobs Inc.