Putting Soy & Other Nutraceuticals Under the Microscope

Soy was one of the hottest ingredients this year at the IFT Annual Meeting & Food Expo. In fact, if ingredients could have their own zodiac chart, this would probably be the Year of the Soy.

Not surprisingly, a high-protein ready-to-eat breakfast cereal made with soy flour as the main ingredient was the winning development at this year’s IFT Student Association Product Development Competition. Called Soy-Pro, the product was created by a student team from Purdue University. The team picked soy because of its nutritional profile and its potential cholesterol-lowering effects and other health benefits. The cereal is said to have a good taste and texture in addition to being good for one’s health.

Numerous studies have focused on soy’s benefits in such areas as cancer, heart disease, osteoporosis, kidney disease, menopause, and cognitive deterioration. Such studies have helped put soy in the spotlight, prompting a growing interest in soy-based products. Technology, which is creating soybean varieties with improved functionality and health benefits, is finding more and more ways to use soybeans, thus sparking product development. Ingredient companies are forming nutraceutical divisions which are helping to quickly and globally commercialize soy-derived isoflavones and other health-promoting ingredients. And the Food and Drug Administration is considering a petition by Protein Technologies International, Inc., St. Louis, Mo., to advise consumers that 25 g of soy protein daily, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease, a health problem associated with many factors.

However, much like what happens with a celebrity, with the increased attention comes more scrutiny, more investigation. Food scientists are asking a wide range of questions. What effect do extrusion and other processes have on isoflavones? How do soy proteins change during storage? How stable are isoflavones at higher temperatures? What factors can have impact on the antioxidant activity of soy protein hydrolysates? What is the effect of pH and salts on the viscosity of soy protein drinks? What are the microbiological, chemical, and sensory effects of products fortified with soy protein? Is it possible to enrich soy protein concentrates? Are there reliable ways to assess the role of isoflavones in various chronic diseases? The list of questions goes on and on.

But I think this attention is necessary, and in some cases, possibly overdue. By looking at soy from every angle, by putting it under a microscope, food scientists are trying to make it better and, in doing so, improve the development of these products. And if they succeed in this endeavor, and if the above health studies are correct, then consumers of the next millennium may have something that delivers on its promises.

Let’s look at some of the ways that researchers are examining soy and the soy-based products that are being developed:

Isoflavones are phyto- or plant-based estrogens, which studies have shown may help lower the risk of certain diseases, particularly those which are hormone related. Soybeans contain isoflavone compounds in aglucone (genistein, daidzein, and glycitein) and beta-glucoside forms. Among the aglucone compounds, genistein exerts the highest anticancer activity. However, because genistein and genistin (beta-glucoside form of genistein) are lost during the production of soy protein concentrate (SPC), an optimized processing condition is needed. The University of Arkansas, Fayetteville, conducted a study to screen soybean varieties for their genistein and genistin contents and optimize conditions to produce SPC enriched with genistein. The researchers found that enzyme treatment and hydrocolloids addition during SPC preparation gave a significant increase of genistein in SPC. The resulting product could find application as an ingredient in numerous food products. (Paper 11A-11)

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Increased evidence has indicated that some food protein hydrolysates contain antioxidant activities. For example, hydrolyzed soy proteins by pepsin and Protease S from a Bacillus sp. were found to act as antioxidants in linoleic acid model systems. Further research is needed, however, to determine the possible inhibitory effect of hydrolyzed soy proteins by different enzymes on lipid oxidation. This may lead to the production of soy protein hydrolysates using different enzymes, and the ability to measure their antioxidant activities in a liposome model system. In a study, the University of Kentucky, Lexington, found that the antioxidant activity of SPI hydrolysates depends greatly on the specific enzymes used. The ability of SPI and its hydrolysates to inhibit lipid oxidation suggests that these prepared proteins can be considered as novel, natural antioxidants for food processing applications. (Paper 50A-41)

Isoflavones, well known phytonutrients found in soybeans and soy-containing foods, have antiestrogenic as well as antioxidant properties. But because of the lack of a database of food values, researchers have had difficulty in directly linking these compounds with risk of chronic diseases. In response, the Nutrient Data Laboratory of USDA/ARS, Riverdale, Md., developed a database on the isoflavone (daidzein, genistein, and glycitein) content of foods, primarily soybeans and soy-containing foods. A nationwide sampling of soy-containing foods in the U.S. was conducted and the foods analyzed for isoflavone content. These data and data from about 30 scientific papers were critically evaluated using methodology developed by USDA. The database is now available to researchers so that they may assess the role of isoflavones in various chronic diseases and may be reached at www.nal.usda.gov/fnic/foodcomp. (Paper 37G-5)

Soybean genotype, processing methods, and additives affect the retention and distribution of isoflavone isomers in soy foods. Additionally, the forms of isoflavones may affect their bioavailability. Limited information is available on the effects of various processing treatments on the retention of isoflavones, especially in processed immature soybean seeds, currently available in some Western markets. Auburn University, Auburn, Ala., conducted a study to (1) assess changes in total isoflavone contents and isomer distribution as affected by boiling, freezing, and freeze drying; and (2) examine selected soybean genotypes for their isoflavone content and distribution at the full seed and fully mature development stages. The study found that the mean retention of total isoflavones was 47% (boiling), 53% (freezing), and 40% (freeze drying), and that plant type has an effect on isoflavone profiles and contents during seed development. (Paper 37G-6)

Growing evidence suggests that isoflavones might play important roles in prevention of degenerative diseases in soy-consuming populations. However, information on thermal stability is needed in designing processes for soy food processing and purification of isoflavones. South Dakota State University, Brookings, found that isoflavone profiles in soy liquor (a by-product from the manufacturing of soy protein concentrates) were changed significantly under higher temperatures. Also total isoflavone concentration was reduced by heating. (Paper 11A-12)

South Dakota State University also performed a study examining changes in isoflavones during extrusion processing. Extrusion processing offers a promising technology, but a better understanding of the effects of extrusion parameters on transformation of isoflavones is needed for more effective product development. (Paper 37G-4)

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The quality of soybeans decreases gradually with prolonged storage. How proteins change and how changed protein conformation affect the food quality of soybeans are not completely understood. Molecular changes in soy proteins as affected by storage of soybeans was studied by North Dakota State University, Fargo. (Paper 65A-32)

Although interest in the health and functional benefits of soy protein continues to grow, fortifying food products with soy can be a challenge. Mississippi State University studied the microbiological, chemical, and sensory effects of soy protein fortification on dairy-based yogurts. The researchers found that yogurts with 1 or 2.5% soy protein were most similar to control products. Development of such products may result in yogurts with additional health benefits but having properties similar to regular yogurts. (Paper 37C-20)

The effect of pH and salts on the viscosity of soy protein drinks was evaluated by The Pennsylvania State University, University Park. Researchers found that the effects of added soy on the viscosity and perceived texture of a fluid food depend strongly on solution conditions. High levels of protein can be used if the pH and salt concentration are kept low (Paper 65A-39).

A walk through Food Expo found a wide range of soy ingredients and applications. What I think is interesting is how many of these products suggest functional or health-promoting improvements over previous versions. Some examples include products that retain higher levels of isoflavones, soybean oils that have lower fat, and soy-based ingredients that offer improved functionality. Also, a number of companies are taking advantage of soy applications to showcase their own ingredients.

Here are a few examples:

The United Soybean Board, Seattle, Wash., unveiled plans to develop a soybean seed with enhanced compositional traits. The effort will result in asoybean oil that has a higher content of oleic acid (65–75%), has a lower linolenic content (3% or lower), has a lower saturated fat profile (7% or lower), and does not require hydrogenation. The initiative team intends to have specific development plans in place by February 2000, introduction of some target traits by 2002, and commercialization by 2005. The initiative will be called Better Bean.

A vegetable oil made from soybeans with half the saturated fat of commodity soybeans was developed by Optimum Quality Grains, LLC, Des Moines, Iowa, in partnership with Iowa State University. Called Nutrium™ Low Saturated Fat Soybean Oil (it was formerly marketed under the name LoSatSoy™), the oil contains 1 g of saturated fat per tablespoon, making possible a 0% saturated fat claim in many food products. Potential applications include salad dressings, mayonnaise, sauces, muffins, cookies, and deli items. The oil is said to taste and perform the same as a commodity soybean oil. The soybean from which the oil is derived was produced using a combination of two conventional breeding techniques: cross breeding and mutagenesis.

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High-sucrose soybeans, also developed by Optimum and part of the Nutrium family, are being used by Devansoy Farms, Carroll, Iowa, in its soymilk, soymilk powder, and soy flours. The improved soybeans are said to be more digestible because they are low in oligosaccharides—the indigestible sugars that cause gas production—and they offer an improved flavor profile and less “beany” taste. The variety of soybeans is not genetically modified.

Soybean isolates which deliver high levels of dispersibility and solubility have been developed by Archer Daniels Midland, Decatur, Ill. NutriSoy™ 940 has a very bland flavor and excellent stability, and delivers a minimum of 2 mg/g of isoflavones. NutriSoy 942, a calcium-fortified version, delivers a calcium-to-protein ratio similar to cow’s milk, without a gritty mouthfeel. These soy isolates are especially useful in dry-mix beverages, dry-mix meal replacements, high-protein/low-carbohydrate nutritional dry blends, or liquid applications requiring high levels of dispersibility and solubility.

A new division of ADM focusing on nutraceuticals highlighted, in particular, NovoSoy™ isoflavones. These ingredients are said to have an isoflavone profile similar to that in the whole soybean. Also, the company recently completed construction of the world’s first commercial plant for isoflavones.

A 3-oz soy patty, marketed under the name LifeBurger™ by Gardenburger, Inc., is enriched with a processed soy product containing high levels of soy isoflavones. Made with SoyLife, which is available from Schouten USA, Minneapolis, Minn., the soy burger is reported to contain a level of isoflavones (30–50 mg) that meets or exceeds the daily amount shown to be beneficial in studies. Ingredient listing for the product includes hydrated soy protein concentrate, water, wheat gluten, isolated soy protein, autolyzed yeast extract, flax seeds, soy isoflavone concentrate flour, wheat fiber, and other ingredients.

Various soy applications were highlighted by Cargill Protein Products, Minneapolis, Minn., at a press conference. These include pasta (6.74 g soy protein/155-g serving), bread (4.13 g/50-g slice), snack bar (6.25 g/1,400-g bar), crackers (3 g/30-g serving), and chocolate snacks (2.6 g/40-g serving).

A new generation of soy protein concentrates, marketed under the name Soyarich, are processed to retain high levels of isoflavones that naturally occur in soybeans while delivering a neutral flavor and smooth mouthfeel to food products. According to its manufacturer, Central Soya Co., Inc., Fort Wayne, Ind., typical levels of genistin and daidzin are 1.5 and 0.75 mg, respectively, per gram of SPC product. The ingredient may be used to fortify such products as beverages, bars, and yogurt.

A chewing gum containing phosphatidylserine (Leci-PS), a soy-based nutrient which can reportedly help prevent or alleviate cognitive deterioration, is available from Lucas Meyer, Inc., Decatur, Ill. The product is called Brain Gum® and was highlighted along with samples of “Smart” snack food products containing PS. Clinical studies have shown that PS can improve memory, concentration, and learning, particularly in older adults.

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Fermented soy flour, marketed under the name Soyarome, was highlighted in two culinary applications: a Thai Peanut Sauce and a Barbecue Sauce. The ingredient, produced by proprietary fermentation and enzyme technologies, may be used to improve the flavor and mouthfeel of sauces, dressings, soups, snacks, cheese products, and baked goods. It has the ability to help flavors linger up to three times longer, and is particularly useful in enhancing vegetable and dairy notes, as well as amplifying spice impact and salt perception. The ingredient was developed by Gist-brocades B.V., which recently merged with DSM to form DSM Food Specialties, Charlotte, N.C.

Soluble soy polysaccharide called Soyafibe-S provides fiber enrichment and may be used as an emulsifier, an adhesive, and a stabilizer. Produced by Fuji Oil using special technologies for extracting and refining water-soluble polysaccharides from soybeans, the ingredient has application in drinkable yogurts, flavor emulsions, powdered flavors, breads, fiber-fortified foods, and other products. Various varieties and grades are available from Mitsubishi International Corp., New York, N.Y.

A family of soy products, marketed under the name Soyful®, was introduced by Zumbro, Inc., Faribault, Minn. Products include soy flours in a variety of forms (full oil, low oil-low fiber, low oil, and modified) and low-oil textured soy protein. According to the manufacturer, processes are used to remove unwanted flavors while retaining many of the desirable components of the soybean, including lecithin, antioxidants, unsaturated fatty acids, and isoflavones.

A nutraceutical ingredient called Beflora Plus® is said to be a proprietary blend of fructooligosaccharides (50%) and soy extract (47.5%). Available from Triarco Industries, Inc., Wayne, N.J., it can act as a prebiotic to nurture or stimulate beneficial bacteria which can help maintain and stabilize intestinal flora. It may be used in functional foods, chewable nutritional supplements, and instant tea formulations.

A soy beverage containing a red-tone caramel color is highlighted by D.D. Williamson & Co., Inc., Louisville, Ky. The drink, derived from concentrated soy milk, includes all the nutritional and health benefits associated with soy protein, combined with an improved appearance.

Like soy, other nutraceutical ingredients such as vitamins, minerals, and herbals have been receiving increasing scrutiny. This can be seen by the number of technical papers on nutraceuticals presented at the 1999 IFT Annual Meeting.

Some examples include a symposium on conjugated linoleic acid, looking at its chemistry and analysis, its assessment in dairy products, factors enriching CLA concentration in ruminant food products, and its use as a functional food constituent for cancer prevention; the binding of vitamin K and vitamin E to bovine beta-lactoglobulin; the structure-functionality of food gums; changes in anthocyanins during juice processing; antioxidant capacity of anthocyanin-rich berries; antioxidant effects of various tea extracts; the functional expression of recombinant human milk proteins in rice; the storage and stability of wheat flour fortified with high levels of vitamin A and iron; studies of the chemical components of sage and their antioxidant and antitumor activities; fortification of chocolate-containing beverages with highly bioavailable iron; increased solubility of copper and iron by substituting organic salts in an experimental liquid infant formula; a protein-based thickener for the elderly dysphagic; and successful nutraceutical product development coupled with sensory evaluation.

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In particular, processing these ingredients presents special challenges, as key nutrient losses can occur. Consequently, a successful incorporation of these ingredients into a nutraceutical application requires a further understanding of the processing conditions, purity of the ingredients, and ingredient interactions and activities. Also, flavor, texture, and appearance have to be carefully considered. For example, masking unpleasant flavors of certain nutraceutical ingredients is essential for a product to be successful.

Takasago International Corp., Rockleigh, N.J., provided a presentation (paper 26-4) covering the role of flavors in masking and enhancing nutraceuticals. Formulating products with health value may involve tastes and aromas not typically found in traditional foods or beverages. Consequently, specific flavors must be developed to cover or mask off-notes and -tastes. The use of descriptive analysis allows the flavor group to understand the attributes of these defects and to create flavors that allow functional products to have enhanced palatability. Also, sensory methods play a major role in determining the nature of the problem and provide the flavorist with basic sensory information for solutions to the problem. These solutions can range from the use of the defect as a flavor in the final flavor to the suppression or removal of the defect.

Meeting these challenges is not easy, but definitely possible, as the following three applications show:

First, a Wall Street Journal article (August 3, 1999) discussed how solving certain functional problems is moving soy milk into the mainstream market. In the past, one problem with soy milk was its bitter, be any taste. However, today, soy milk producers are offering flavors such as chocolate, vanilla, and strawberry to mask the soybean taste. Also, certain production processes have been improved so that even unflavored varieties may taste like regular milk. Another problem associated with consumption of soy milk has been intestinal gas, but this may be solved by removing gas-fermenting carbohydrates from the soy.

Second, at the IFT Food Expo, Folexco/East Earth Herb, Montgomeryville, Pa., highlighted a crisped rice cereal which contained 1 g of ginkgo biloba per 33-g serving. A flavor reminiscent of an orange Dreamsicle was used to mask the ginkgo’s rather undesirable flavor.

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Third, a fortified burrito, introduced at Food Expo, was reported to deliver 100% of the Daily Value of 23 essential vitamins and minerals in a single serving. Called the Dilberito™, the product is available from Scott Adams Foods, Inc., Newton, N.J.—a company founded by the creator of the comic strip Dilbert. The burrito, which is vegetarian, frozen, and dual-ovenable, is formulated with a custom premix available from BASF Corp., Mount Olive, N.J. The challenge was to develop a premix that supplemented the product’s natural nutrients, providing all the nutrients necessary for one day, while not affecting the distinctive flavors of the four varieties (Mexican, Garlic & Herb, Barbecue, and Indian). I sampled the burrito (several times, I might add) and found it to be very tasty and well worth the efforts of the companies involved. The product will soon be in frozen food cases of supermarkets and convenience stores across the nation.

In addition to processing and sensory considerations, a number of other areas have to be examined. Maintaining the active properties of a nutraceutical throughout its shelf life is very important. According to a presentation given by T. Labuza, University of Minnesota (paper 4-4), if an active ingredient in a nutraceutical product degrades over time, the product may not meet its claim and could be declared misbranded. Consumers using the product will not get the benefit they thought they were getting, and may have a product contaminated with unsafe breakdown intermediates, raising a safety issue.

As government agencies and consumers seek higher-quality herbal products, the issue of standardization becomes more important than ever. Herbal product assays, in particular the use of quantitative chemical methods to standardize herbal extracts on marker compounds, was reviewed (paper 4-5).

Ingredients are available from a variety of sources. Factors such as variety, geographic origin, and climatic growth conditions have been reported to influence an ingredient’s specific nutrient compositions, which are key to the effectiveness of functional food products. Appropriate use of sensory methodology will enable product developers to decide whether or not one source may be substituted for another. McCormick & Co., Inc., Hunt Valley, Md., reviewed sensory methods used to measure the variation in the sensory properties of spices, herbs, alliums, and vanilla from different sources (paper 26-3).

In short, food product developers must learn more and more about safety, stability, processing, and regulations in the area of nutraceuticals. And, of course, more health studies need to be done. A nutraceutical such as an herbal is not right for everyone. For example, persons with allergies or certain health problems or having surgery need to consult physicians. And, finally, when viewing the wide array of applications using a nutraceutical ingredient, one has to be aware of dosage levels and the actual effect—if any—that application may have on the individual. In other words, how much is marketing and how much is scientific fact. Certainly the area of nutraceuticals is creating some interesting situations where technology push vs marketing pull is at work. This is okay, as long as both sides use their information to the fullest.

by DONALD E. PSZCZOLA
Associate Editor