Pull a baked product off the shelf at a local supermarket and soy is likely to appear on the ingredient label. In the past 10 years, soy has gone from a little known food in the United States to a highly sought after product; and now stands as both a fuel and a commonly used ingredient, hailed for both its healthful and functional benefits.
Soy's popularity began to rise in 1999 when the FDA confirmed that consuming 25 grams of soy protein daily lowered LDL or “bad” cholesterol. It approved a claim that a product can be listed as having heart benefits if it contains 6.25 grams of soy protein, which is 25 percent of the recommended daily amount.
In 2000, the American Heart Association (AHA) released a statement suggesting that “it is prudent to recommend including soy protein foods in a diet low in saturated fat and cholesterol.”
A more recent study from Northwestern University's Feinberg School of Medicine, Chicago, shows the isoflavones in soy may benefit asthma patients. Other studies have shown that isoflavones may help protect against some cancers.
Soy is the only commonly-consumed food that offers isoflavones — primarily genistein and daidzein — a type of phytochemical, or plant chemical. Many phytochemicals offer health benefits in relation to cancer and heart disease, according to the SoyFoods Council. Researchers continue to examine whether isoflavones alone hold healthful benefits or if soy protein combined with isoflavones produces the positive effects, notes Mian Riaz, Ph.D., director of food protein research and development, Texas A&M University, College Station.
While studies have shown soy may protect against osteoporosis and some cancers, help control weight and ease menopausal symptoms in women, other studies have contradicted these results. In 2006, an AHA committee analyzed the results of 22 randomized studies that took place in the 1990s and early 2000s in an effort to reach one conclusion. They found soy protein only lowered LDL cholesterol by 3 percent and had little to no effect on the risk factors for heart disease. Results were mixed regarding soy's ability to slow postmenopausal bone loss. Soy's effect on the prevention of certain cancers was found inconclusive. The study, however, did confirm that using soy protein could be beneficial for health because of its high content of polyunsaturated fats, fiber, vitamins, minerals and low saturated fat.
“Initial estimates for soy had been that it lowered cholesterol by at least 10 percent, but in the last seven to eight years the studies have shown smaller decreases,” says Mark Messina, Ph.D., consultant to soy companies and adjunct associate professor with Loma Linda University, Loma Linda, Calif. “A 3 percent decrease in LDL as reported in the 2006 AHA analysis was on the low end of the estimated range as other similar analyses have shown as much as a 5 percent reduction. Although a lot less potent than drugs, shifting the mean cholesterol of the population downward by 3 percent to 5 percent is still quite important; as a result, heart disease rates will likely decrease by as much as 10 percent. Soy is definitely a heart-healthy food. It isn't going to lower your cholesterol to the target by itself, but definitely will provide benefits as part of a balanced diet.”
More recent studies continue to show that soy may contain disease fighting and postmenopausal benefits. According to a study conducted by researchers from The National Cancer Institute, women who ate about one serving of soy per day between the ages of 5 and 11 were 58 percent less likely to develop breast cancer than were women who consumed little soy when young, Messina says.
In 2007, a study published in Maturitas, The Official Journal of the European Menopause and Andropause Society, concluded soy isoflavone extract exerted favorable effects on vasomotor symptoms and was a safe, effective alternative therapy for postmenopausal women. A study published June 2007 in the Annals of Internal Medicine concluded “24 months of treatment with genistein has positive effects on bone mineral density in osteopenic postmenopausal women.”
Thus the debates and studies continue regarding the scope of soy's healthful potential.
Soy is especially beneficial to bakers because it offers a variety of functional attributes, including the ability to bind water, replace allergens, cut costs, improve texture and shelf life, whiten bread and help achieve finished product elasticity.
Whole soybeans contain 35 percent to 36 percent protein. When oil is removed from the soybean, the protein content increases to 50 percent, notes Riaz. Soy protein concentrate is produced at 65 percent protein after some of the carbohydrates and sugars are removed. Soy protein concentrate can be further processed into soy protein isolate at 90 percent protein, he adds.
Both processing technology and flavor have come a long way since soy was first introduced to the baking industry. “Processing technology has improved so much that now manufacturers can get rid of a lot of beany flavor, especially when processing flour. The soy is further processed in an extruder and using techniques with steam and deodorization,” Riaz says. He adds that today, most companies producing soy products offer masking flavors to cover the remaining beany flavor in soy; a change from five to 10 years ago when few companies had such masking flavors available.
Givaudan Taste Essentials offers a line of flavor modifiers and masking agents to aid in the challenges associated with flavoring soy products, says Jeff Spencer, director of flavor creation, Givaudan, Cincinnati.
Not only are more masking flavors available, but some companies are using mechanical extraction methods in place of hexane extraction, which is not permitted for organic products, says Peggy Dantuma, manager, bakery applications lab, Kerry Ingredients, Hoffman Estates, Ill. Hexane is used as a solvent to strip the oil from the soy. Using hexane extraction reportedly gives the soy a bitter aftertaste. Kerry uses mechanical extraction methods and also offers non-genetically modified soy.
These days, soybeans, like other oilseed crops, are being converted into biodiesel fuel. “The same farmers grow soybeans and corn. Corn is being used to make ethanol. Farmers can sell their corn and get subsidies. Therefore, most farmers are changing their acreage from soybeans to mostly corn,” Riaz says. The result is dwindling soybean crops at a time when their demand as both a fuel and a food is climbing, causing prices to escalate. “Strong soybean meal use and the anticipation of future needs for oil for biodiesel production have fueled soybean demand, which has never been higher,” Qualisoy reports. Trait-enhanced soybeans also are in demand to replace hydrogenated oils and help bakers achieve no-trans fat goals. The 2007 soybean crop is estimated to increase in price by 40 percent when compared to the previous year. Carryover stocks into 2008 are estimated by the USDA to be 180 million bushels, the lowest since September 2004.
During the Atkins diet craze, the demand for soy products surged because of soy's protein benefits. Today, the soy market has stablized but remains strong, Riaz says.
Soy is a relative newcomer to the baking industry with a lot still to be studied, Dantuma says. “I think you're going to continue to see many different ways of using soy. In the baking industry, everything is focused around nutrition, health and cost savings, which soy provides [compared to other proteins],” she adds.
Soy fiber can hold up to nine times its weight in water, and can be used by bakers seeking a fiber claim. It is often used in tortillas, breads, cakes, muffins or nutritional bars.
“If we took a tortilla and added a small amount of soy fiber it would bind more water, therefore keeping the tortillas flexible and soft, so you achieve a longer shelf life,” says Peggy Dantuma, manager, bakery applications lab, Kerry Ingredients, Hoffman Estates, Ill.
Soy nuts resemble tree nuts or legumes. They work as an alternative to tree nuts when bakers are looking to limit nuts for either cost savings or allergen concerns. High in fiber, they also can be used as toppings or inclusions to add texture or appearance. Soy nuts can be flavored to taste like a pecan, hazelnut or walnut. They often are used in cookies, muffins and cereal bars.
Soy flour comes in low fat and full fat varieties and can be used to replace egg or nonfat dry milk in formulations. “Using full fat soy flour, you can do a 20 percent to 35 percent replacement in a cake or a muffin. In a pancake or waffle you can do close to a 100 percent replacement. It is very formula specific as to how much egg you can replace,” Dantuma says.
One kg of soy flour will bind with about 1.5 kg of water, says Mian Riaz, Ph.D., director of food protein research and development, Texas A&M University, College Station. This water holding capacity can increase shelf life and the amount of product produced. “If they are making one batch of 50 loaves, they can produce 52 loaves. That is two loaves extra because of the extra water holding capacity,” Riaz says.
Enzyme active soy flour can be used in place of a dough conditioner as a crumb whitener in a bread dough. When whitening bread it can be used at less than 0.5 percent, Riaz notes.
Soy protein isolate binds about five times its weight in water, second only to soy fiber, Dantuma says. It is used primarily for nutritional enhancement. Bakers can use soy protein isolate to increase their overall protein claim or to balance the essential amino acids in a product. “If you combine the amino acids in a soy protein isolate with wheat, it would be a more nutritionally complete protein,” Dantuma notes. “There are also many studies on soy protein in that it helps lower serum cholesterol levels,” she adds. It is often used to replace milk proteins to get rid of a dairy allergen, and appears in protein bars and cookies.
Soy protein concentrate has a protein level above 65 percent protein, usually between 69 percent to 70 percent protein on a dry basis, says Homer Showman, director of R&D, proteins and nutrition, Kerry Ingredients.?Most concentrates have the soluble carbohydrates removed and the fiber is left with the protein. ?The fiber remaining is around 20 percent to 22 percent of the concentrate.
Textured vegetable protein is often used as inclusions in food bars. The protein is usually sent to bakers as a raw ingredient, and they use their own flavor profiles to flavor the protein to fit a desired finished product.