SOYBEAN NEW USES RICHARD A. VIERLING Indiana Crop Improvement Association and Department of Agronomy, Purdue University West Lafayette, IN 47907 History The soybean (Glycine max) is often called the miracle crop. It is the world’s foremost provider of protein and oil. As early as 5,000 years ago, farmers in China grew soybeans. Soybeans were mechanically crushed for the oil, which was used for lubricants, lamp oil, coatings, cosmetics and waterproofing. In 1804, a Yankee clipper ship brought soybeans to the U.S. In 1829, U.S. farmers first grew soybeans. They raised a variety for soy sauce. During the Civil War, soldiers used soybeans as “coffee berries” to brew “coffee” when real coffee was scarce. In the late 1800s many farmers began to grow soybeans as a forage for cattle. In 1904, at the Tuskeegee Institute in Tuskeegee, AL., George Washington Carver began studying the soybean. His discoveries changed the way people thought about the soybean; no longer was it just a forage crop. Now its beans provided valuable protein and oil. For a product with no commercial value at the turn of the century, soybean is now the second largest cash crop in the U.S., valued at $16 billion annually. By 1929, U.S. soybean production had grown to nine million bushels. That year, soybean pioneers W. J. Morse and P. H. Dorsett left on a two-year odyssey to China during which he gathered more than 10,000 soybean varieties for U.S. researchers to study. Some of these varieties laid the foundation for the rapid ascension of the U.S. as the world leader in soybean production. Before World War II, the United States imported 40 percent of its edible fats and oil. At the advent of the war, this oil supply was cut. Processors turned to soybean oil. By 1940, the U.S. soybean crop had grown to 78 million bushels harvested on five million acres, and the United States was a net exporter of soybeans and soybean products. In the early 1950s soybean meal became available as a low cost, high protein feed ingredient, triggering an explosion in U.S. livestock and poultry production. In the 1960s, Europe experienced a similar phenomenon. By 1970, four-fifths of all soybean meal was consumed by poultry and hogs, and around the world, soybeans were supplying more protein for livestock and poultry than any other single source. The demand for soy oil increased with the increased acceptance of soy oil margarine, shortening and cooking oils. During the 1980s, soybean consumption grew with the increased popularity of soyfoods, such as tofu, soy milk, soy flour, and soy sauce. The 1990s saw an increase in soybean demand due to the new awareness of the health benefits of consuming soy products. The first industrial use was the replacement of soybean oil for linseed oil in the 1910s. During WWI, soy oil was routinely used instead of linseed oil for paints, explosives and lubricants. During this time, the first soy-based plastics and celluloids were made. The 1920s saw the development of soy glues for wall paper, wood adhesives and paper coatings. The 1930 and 40s saw an increase in research for the industrial applications of soy products. Products included soy textile fibers, foams for fire extinguishers, plastics and lubricants. Henry Ford took an axe to a car trunk made with soybean plastic to prove its durability. The publicity increased the soybean’s popularity. The end of WWII, coupled with the availability of cheap petroleum was disastrous for industrial uses of soy. Petroleum quickly replaced soy due to increased demand volume from a rapidly growing chemical industry, expense and^^^Document Error^^^biochemical inertness. Synthetic fibers such as nylon, polyethylene and polystyrene replaced soy protein plastics and fibers. ^^^Document Error^^^ Current U.S. Production ^^^Document Error^^^ (64.83 million metric tons), and the crop value reached a record high of $16,317 million on an average price paid to farmers of $6.85 per bushel ($252.00 per metric ton), the highest average price since 1988. In 1996, soybeans represented 52 percent of world oilseed production, and 49 percent of those soybeans were produced in the United States, which represents 69 percent of the world’s soybean trade Every other row of soybeans grown in the U.S. goes into the export market. Japan is the single largest soybean customer and the European Union makes up the largest collective market. Canada was the largest customer for U.S. soybean meal, and China became the largest customer for U.S. soybean oil, the third largest customer for U.S. soybean meal and the sixth largest customer for U.S. whole soybeans. Domestically, soybeans provided 82 percent of the edible consumption of fats and oils in the United States. The domestic crush level reached a record 1,425 million bushels (38.79 million metric tons), while U.S. ending stocks of soybeans were 125 million bushels (3.4 million metric tons), the lowest level in twenty years. Processing Soybean processing is the conversion of soybeans into three basic components, oil, meal and hulls. The first large scale continuous solvent extraction plant in the U.S. was introduced from Germany in 1934. The process quickly replaced the continuous screw press process by 1940. An intro to processing: 1. Cleaning and drying 2. Preparation - consists of cleaning, cracking, dehulling, conditioning and flaking 3. Extraction - oil is washed out of flakes using hexane 4. Distillation - removing hexane from oil 5. Desolventizing and toasting flakes - removing hexane from meal 6. Solvent recovery 7. Hull grinding 8. Meal processing - drying, cooling, grinding and screening 9. Caustic refining - removal of phosphitides, free fatty acids, color bodies and metallic pro-oxidants 10. Bleaching - removal of soaps 11. Hydrogenation 12. Deodorization Various modifications and variations on the above procedure, generate several forms of soy meal and oil. Soy protein can take the form of 44-48% protein soybean meal, edible defatted flakes, soy grits, soy flour, textured soy flour, soy molasses, soy protein concentrate and isolated soy proteins. Soy oil can be crude, feed fat, salad oil, lecithin and shortening or margarine. Hulls are used as a dietary fiber supplement, or an ingredient in bread, cereal and snacks or a source of peroxidase. New and Rediscovered Uses I have added rediscovered to the title of this section because some uses of soybean uses are no different from the uses 70 years ago, but with current, modern chemical technologies, the soy products are drastically different from the soy products used in the past. New and rediscovered uses for soy components include: Protein adhesives asphalt emulsions packaging film leather substitutes particle board textiles plastics polymers fibers coatings fire control foams emulsion stabilizers soy-lignin composites soy-myosin TVP roof coatings nutraceuticals expanded foam fertilizer Lipids anticorrosion agents protective coatings fabric softeners antifoaming agents emulsifiers polymers and epoxies putty and caulk metal casting lubricants fungicides disinfectants explosives pharmaceuticals plastics chemical intermediates molecular filtration chelation fuels and solvents release agents spray adjuvants dust control liquid waxes crayons surfactant Hulls peroxidas Forces of Change 1. New product 2. Better product 3. Lower cost or higher profitability 4. Increased health benefits 5. Environmental friendliness 6. Legislation I believe that the two main reasons for the interest in soy based industrial products are environmental friendliness and legislation, specifically the Clean Air Act of 1990. Mass media coverage of consumer use and disposal of inert petroleum plastics, fuel consumption, waste oil disposal and other forms of water and air pollution have raised the public’s consciousness of our society’s dependance on petrochemicals. This was highlighted by the oil embargo during the 1970s. The increased awareness of environmental issues has lead to a refocusing of research into renewable resources from domestically produced raw materials. Consumers are actively searching for more healthful meal alternatives and have changed their diets by eating more fruits, vegetables and fiber and reducing their intake of red meat, dairy products and fats. Western societies are afflicted by an increasing prevalence of cancer, cardiovascular disease, obesity, and osteoporosis compared with Eastern societies that have increased levels of soy in their diet. Coincidentally, a shift from a traditional soy Asian diet in Asian urban areas to a more western diet has lead to a notable increase in cancer and cardiovascular disease. This increased nutritional awareness of consumers has been responsible for increased research into the health benefits of soy. An important factor in the decision to use or switch to soy-based products is will it be profitable. Profitability can be divided into several categories. High volume/low margin food fuels lubricants Intermediate volume/ intermediate margin surfactants plasticizers corrosion inhibitors soaps inks coatings cosmetics adhesives food additives Low volume/high margin therapeutics pharmaceuticals bioseparation nanoparticles cyclodextrins peroxidase for diagnostics functional foods Industrial Uses Soy Solvents Soy solvents, methyl and ethyl soyate, are made by the transesterification of refined soybean oil and is currently being used in many products. They are essentially nontoxic, biodegradable, high boiling and flash points, and low volatile air emissions. Uses include replacement of petroleum solvents, industrial and hand cleaners, degreasers, paint strippers, wood stain, and bioremediation. Adhesives and Binders Soy flour adhesives are made from finely-ground, defatted meal. Soy adhesives are a rediscovered use due to the Clean Air Act of 1990. Formaldehyde from current adhesives and phenoxy compounds from phenol resins are under attack because they contribute to air emissions of volatile organic compounds (VOC). Soy adhesives in combination with phenol-resorcinol-formaldehyde adhesives can reduce VOC emissions and pure soy adhesive can eliminate VOC emissions. Soy-based binders can be used as a replacement of urea formaldehyde or phenol formaldehyde in the production of particle board, oriented strand board or plywood. Lubricants Soy oil lubricants are driven by environmental concerns, since millions of gallons of petroleum oils, greases and hydraulic fluids leak into the environment every year. Soy lubricants are not suited for all uses because of limitations in thermal, hydrolytic and oxidative stability. Advantages of soy lubricants are high lubricity, high viscosity index, low evaporation loss and biodegradability. Applications include pumps, switches and ropes where lubricants can directly move into the environment. Surfactants Soy oil derivatives contain high levels of C-18 stearic acid and linoleic acid, which make good surfactants. Currently the $10 billion per year surfactant industry, including detergents, cloths’ softeners and soaps, is searching for environmentally friendly, biodegradable surfactants. Soybean fatty esters are a new crop spray adjuvant that is the preferred method of applying herbicides to right of ways by the U.S. Forest Service. Paints and Coatings Regulatory requirements for low VOC, by the exclusion of non-aqueous solvents from paints and coatings is fueling research using epoxidized soybean oil as a base resin. In a novel use, a soy derived lecithin is used as an emulsifier for edible food coating. Plastics Biodegradability, fire resistance, coatability, adsorption, absorption, ultraviolet and infrared transmission, and antistatic, are some potential attributes of soy oil and protein derived plastics. Soy polyurethane foams have excellent strength/weight ratio, superior insulating abilities and enhanced energy absorbing performance. Potential products include molded pet toys, foam insulation, mulching film, trash and grocery bags and extrudable plastics. Functional Foods Soybeans have been described as nutritional powerhouses. For thousands of years, Chinese herbalists have recognized the medicinal properties of soybeans, but only recently have these properties filtered into Western culture. Food technologists have struggled with making soybeans palatable to Western consumers. This has lead to a sophisticated fractionation of soybeans and a systematic examination of the nutritional value of each fraction. Soybeans are rich in vitamins (many B and E) and minerals, including calcium, zinc, and iron. In addition, soybeans contain linoleic acid, an omega-3 fatty acid, and are an excellent source of dietary fiber. An exciting component of soy products are the phytochemicals, compounds that are not nutrients per se, but have beneficial biological effects. These phytochemicals include, isoflavones (genistein and daidzein), inositol hexaphosphate, plant sterols and saponins. When one considers the percentage of cancer deaths that are attributable to environmental factors, at least 35% of these cancers may apparently be related to diet. Potential Health Benefits of Soybean Disease State Cancer Cardiovascular Disease Osteoporosis Renal Disease Gallstones Gastointestinal Disorders Mechanisms of Benefits Soybean diets are associated with lower prevalence of many cancers. Isoflavones are tumoricidal, antiestrogenic, antiangiogenic, antioxidant and inhibit protease enzymes. Saponins, phytosterols, isoflavones, and lecithin play a role in lowering blood cholesterol, which is beneficial in preventing arteriosclerosis causing dementia, strike, coronary artery disease, and peripheral vascular disease. Soy protein seems beneficial in preventing bone loss. Soy protein diets cause metabolic improvements in renal disease. Soy products reduce cholesterol and my help dissolve cholesterol gallstones. Soy fiber helps lower incidence of colon cancer, relieve divericular disease and primary treatment for irritable bowel. Isoflavones are the most widely studied phytochemical found in soybeans. Considerable evidence exists that isoflavones exert estrogenic effects. This antiestrogenic effect may be one of the more important ways they exert an anticancer effect. Researchers believe that the competition between isoflavones and estrogen for binding to estrogen receptors is critical. The surplus estrogen then sends a message back to stop production of hormones. The theory is that women, who ingest phytoestrogens daily, has a lower production rate of endogenous estrogen and thus a lower risk for hormone-related cancers, especially breast cancer. Isoflavones also inhibit the production of new blood vessels, which is required for tumor growth. Peroxidase Uses The primary function of peroxidase enzymes is to oxidize a variety of hydrogen donors at the expense of peroxide or molecular oxygen in oxidasic reactions. Oxidation has been called the technology of the nineties because as environmental needs and regulations continue to become more severe, destructive treatment technologies consistent with waste minimization must be developed. Because of the oxidative nature of peroxidase, there are several areas where it could replace current chemical oxidation techniques. Soybean seed coat peroxidase is atypical in its high thermal stability (> 85 oC) and its high reactivity with a wide range of substrates. The soybean peroxidase industry is less than four years old, but has seen considerable growth and there is room for increased growth. This new industry has been driven by environmental concerns and the ability of soybean peroxidase to generate new, unique products. Peroxidase products or uses: 1. Specialty chemicals - these are new and unique products that can only be made with peroxidase 2. Engineering of new product compounds 3. Enzymatic antioxidant 4. Dough conditioning - substitute for the toxic chemical potassium bromate 5. Medical diagnostics 6. Intrinsically conductive polymers 7. Cloths’ detergent additive 8. Formaldehyde free phenolic resins - peroxidase can directly conjugate phenolic rings without an intermediate carbon like formaldehyde. This has the advantage that there is no residual formaldehyde to leach out of the products. Conclusion Soybeans have well over 1000 uses and this is just a small sample of some of the more promising areas. Some aforementioned uses have commercially available soy products but for most, additional product development in needed to make the soy product a viable commercial alternative to current products. Technical feasibility of soy products does in no way ensure they will ever be a commercial succe Soybeans have well over 1000 uses and this is just a small sample of some of the more promising areas. Some aforementioned uses have commercially available soy products but for most, additional product development in needed to make the soy product a viable commercial alternative to current products. Technical feasibility of soy products does in no way ensure they will ever be a commercial success.