SOY, More Than a Hill of Beans.

Tofu isn't the only way to add the health benefits of soy to your diet.

Although soybeans have been cultivated in China for animal and human use since the eleventh century B.C., large-scale soybean farming in North America did not occur until the 1920s. Even then, soybeans (about 21 percent oil and 40 percent protein) were raised mainly for oil, with the protein, carbohydrate, fiber, and mineral residue being used for animal feed. With the exception of soy sauce, soy protein was not used extensively for human consumption. All that has changed.

Today in North America soybeans play an increasingly important role in the diet. Even nonvegetarians consume them in the form of meat extenders, while vegetarians make of them almost a second staff of life. There is a nearly Jack-and-the-bean-stalk-like quality about the history of this lowly legume (now the second leading crop in the United States).

By the late 1930s, with the increase of soy oil production, manufacturers became motivated to develop soy protein foods and feeds with the inexpensive protein by-product. Gradually these were introduced to consumers who were allergic to specific animal products, those interested in alternatives to animal-based foods, and those requiring an inexpensive dietary protein source. Among others, Dr. Harry Miller, who had spent years as a missionary physician in China, began introducing a few soy products including a beverage. Later Dr. Miller would receive the first American Medical Association approval of a soy-based infant formula. In the 1940s and 1950s Cornell University professor of nutrition Clive M. McCay, Ph.D., did much to promote the use of soy and soy products.

With increased soy availability, there is now rapidly increasing acceptance of soy products. This is thought to be because of (1) the high biological value of soy protein, (2) scientific and technological advances making possible acceptable soy-based food textures and flavors, (3) the trend toward decreased animal protein consumption, and (4) the ever-increasing evidence that soy and other plants contain a multitude of "nutrient" chemicals that decrease the incidence and progression of coronary artery disease, other chronic diseases, and various types of cancerous tumors.

Types of Soy Foods

Vegetarians in North America consume various types of soy products. Among the simplest to prepare is the whole bean. There is only one problem. Because soybeans contain little starch (but short polysaccharide polymers), have high oil content, and are compact, they do not soften readily when cooked. It is helpful to know that varieties bred to be eaten rather than processed soften more than common field varieties, and most varieties are acceptably soft if harvested in the green, immature state.

Dry Soybeans

Since canned or frozen soybeans are not readily available in supermarkets (as are pintos, limas, and other beans) people generally cook the dried mature beans after washing and soaking them overnight (or for a shorter time, at a higher temperature) to reduce cooking time.

During the soak, about 30 percent of raffinose and 20 percent of stachyose, the oligosaccharides that greatly contribute to flatulence, are leached into the soak water. Draining the soak water and replacing it with fresh water for cooking reduces the amount of flatulence the cooked beans may cause. It appears that the long 20 [degrees] C soak yields the tenderest product with the best color and flavor.

To further reduce cooking time, some drain the soaked beans, spread them on a Teflon cookie sheet one layer deep, and place them in the freezer. Soybeans thus individually quick frozen (IQF) may be stored as long as six months in a tightly closed plastic bag and used as needed for cooking. IQF soybeans, ground or blended and combined with appropriate ingredients, make delicious patties, waffles, etc.

Natto

Incubated cooked soybeans cultured with Bacillus natto develop a thick, sticky coating and a distinct flavor. Natto, available in many markets in eastern Asia, is used in some Japanese dishes.

Soynuts

Dried mature soybeans soaked overnight can be deep-fat or air roasted with or without the skin to make soynuts, a product similar to roasted peanuts. Quick-frozen soybeans produce a slightly more appealing product.

Soybean Sprouts

Sprouts can be served parboiled in fresh salads as well as steamed or cooked in Asian dishes. The nutrient profile is much like that of a fresh vegetable. Any variety of dried mature soybeans may be used to sprout; however, special varieties have been developed for this purpose. After soaking overnight, the beans are rinsed and placed in a cool area to drain. They are then rinsed with water about four or five times a day for three to five days to keep them moist and retard microbial growth until the sprouts are about two to three inches long. Rinsed, wrapped in a moist towel, and stored in a sealed plastic bag, the sprouts can be refrigerated for three to five days.

Soy Milk

Many vegetarians consume a soy beverage to replace cow's milk. Commercial soy milk products fall into three categories: (1) fat emulsions, (2) water extractions of whole ground soybeans, and (3) soy protein isolate beverages. The fat emulsion-type is easiest to make tasty, but provides few nutrients other than fat calories. The soy protein isolate-type is the next easiest to make tasty, and if it is fortified with essential vitamins and minerals is a nourishing product. The water extract of the whole soybean is the most difficult to make tasty, but there are a few such commercial products that meet even the strictest taste criteria.

In choosing a soy milk beverage, vegetarian consumers should be certain it contains certain necessary fortified nutrients. It is strongly urged that each day a vegetarian consume a known source of vitamin [B.sub.12]. Soy milk is a good vehicle for the delivery of this fortified vitamin.

Soy milk can be purchased plain or flavored in sterilized liquid "brick packs" (brick-shaped fiberboard laminated cartons) or in powdered form. It may be used in most any way that milk can. Flavorwise, some types of soy milk are especially suitable for drinking, while others work well in cooking or as a base for a delightful soy mayonnaise or salad dressing substitute.

Okara

Okara, the pulp left over from making soy milk, is used with other ingredients to make patties and various entries. If the beans are dehulled before making the soy milk, the okara will have a more acceptable texture.

Tofu

Commercial tofu is available in either fresh tubs (which need refrigeration) or sterilized brick packs (which do not). Soft, medium, or firm styles are available. (The softer the tofu, the higher the water content.) Since tofu is very bland tasting and will absorb flavors, it is easy to season to suit the discriminating palate. Popular ways to consume tofu are: scrambled with a little chicken-style seasoning, onion powder, and turmeric; fried and salted; or as an ingredient in a patty, entree, salad, or dessert. (As interest in tofu increases, new varieties of recipes proliferate.) Tofu can be frozen, then thawed and drained to produce a texture more like chicken or fish.

Yuba (Dried Soy Film)

When soy milk is simmered, a skin forms on the surface. The paper-thin skin can be pulled off and dried. This "yuba," available in some Asian markets, is used in Japanese specialty dishes.

Miso

Miso, available in most Asian markets, is a light-brown fermented soybean paste used as a seasoning. It is commercially made from steamed soaked soybeans cultured with Aspergillus oryzae, Aspergillus sojae, and Rhizopus oligosporus, and allowed to ferment for about nine months.

Soy Sauce

Soy sauce is used as a flavoring for many types of dishes other than vegetarian; however, it becomes almost indispensable for rice-based diets. There are two ways in which soy sauce can be made: (1) the traditional method, which is much like making miso except for a longer fermentation time and an extraction with a brine solution, and (2) the hydrolyzed method, using either soybeans or soybean meal, and perhaps wheat, which are hydrolyzed with hydrochloric acid, and then neutralized with sodium hydroxide. The two products taste somewhat alike, but the fermentation process of the first technique produces a decidedly more aromatic product.

Tempeh 

Originating in Indonesia, tempeh is a firm whitish soy product having a fresh, yeasty, clean aroma. It is available in specialty stores or may be made at home by briefly cooking dehulled soaked soybeans, inoculating them with Rhizopus oligosporus (some commercial cultures are labeled "ragi tempeh"), wrapped in lightly steamed banana or other large leaves, and incubated in a warm place for 24 to 48 hours. The beans will be permeated with a white mycelial mass to form a firm cake. The cake can be thinly sliced, salted, and deep-fat fried in coconut oil, placed in soups and stews, or used in the same way as hamburger patties.

Fresh Green Soybeans (Edamame)

Green, immature, fresh soybeans in the pod can be shelled easily after being covered with boiling water for about five to 10 minutes, depending on maturity and size. One pound of pods yields about 1.75 cups of shelled beans. Cooking requires simmering them (about two volumes of shelled fresh green soybeans in one volume of salted boiling water) for 10 to 20 minutes. An alternative is to wash the fresh pods, simmer them in salted water, and then open the pods and scoop out the tender beans for eating.

Soy Flour and Soy Grits

Soy flour or soy grits is used mainly in baked goods (to increase protein quality and lightness of texture) and entrees (to increase protein quality). Lacking gluten, soy flour or grits cannot replace more than 25 percent of wheat flour in baked goods. There are two types of soy flour: full fat (found only in some specialty shops), and defatted. Defatted soy flour is produced from soy flakes from which the soy oil has been removed. Soy grits consist of particles coarser than those of soy flour.

Soy Protein Concentrate and Soy Protein Isolate

Soy protein concentrate and soy protein isolate are used commercially as convenient ingredients to increase protein content or adjust textural qualities in food products without causing gas. (The oligosaccarides of raffinose and stachyose are absent in these products.) Both concentrate and isolate are used in analogs as well as binders in meat products. Flavorwise both are bland. The soy protein concentrate (70-74 percent protein) is made by removing most of the oil, soluble carbohydrates, minerals, and some of the vitamins. Soy protein isolate (90-97 percent protein) is made by isolating the soy protein to the exclusion of almost everything else.

Meat Analogs Made From Soy

For convenience, some vegetarians, as well as nonvegetarians, use commercially prepared meat analogs made from a variety of ingredients including soy, wheat gluten, peanut meal, and wheat germ, to mention a few. The number of food companies producing them grows each year. This discussion will be limited to meat analogs made from soy.

Those who become vegetarians soon realize that vegetarian foods tend to have a softer texture than meat. Since the turn of the century food researchers such as John Harvey Kellogg, of Battle Creek Sanitarium fame, have sought ways to texturize plant-based proteins. Though in 1907 Kellogg was awarded patent 869,371 for a texturized vegetable-based protein, no further patents were awarded until after 1950. As a spinoff from World War II research, two types of textured products appeared on the market: (1) soy fiber spun from soy protein isolate and held together with a binder containing flavorings, and (2) soy protein texturized by extruding flavored concentrate or flour through a die at high temperature and pressure to help align the protein molecules. The product is then dried. Either of these may also be used as meat extenders. The spun soy fiber products resembling pieces or slices of meat, fish, or poultry are usually canned or frozen and require little if any preparation. Extruded soy products, usually dehydrated, may be made to resemble bits of bacon, ground beef, or chunks of meat or poultry. They may be used in stews, vegetarian entrees, salads, spaghetti sauce, vegetarian chili, tacos, etc.

With many vegetarian soy products now consumed in the Western world as well as in the East, lush soybean fields stretch far and wide. From beverages to burgers, from tempeh to tofu, soy--the amazing "beanstalk"--continues to provide significant amounts of high-quality protein and nourish billions worldwide.

Kenneth I. Burke is the professor/associate chairman of the Department of Nutrition and Dietetics at Loma Linda University in Loma Linda, California.