In the Far East, traditionally, soybeans are made into various foods for human consumption, whereas in the West, most soybeans are crushed into oil and defatted meal. Due to this difference in soybean use, two different types of soybeans have emerged; food beans and oil beans (Liu et al., 1995; Orthoefer and Liu, 1995; Wilson, 1995). Annually, the United States exports 10 to 15 percent of the soybean production estimated at 6 to 7 million metric tonnes, to Japan, Korea and Taiwan. Most of this portion is used for whole bean applications (Motoki and Seguro, 1994).

The traditional soyfoods include the nonfermented and fermented Oriental soyfoods. Among the nonfermented soyfoods, tofu is the most popular, followed by soymilk and soy sprouts. Other includes okara, roasted soy nuts or flour, yuba, fresh immature soybeans, sweet beans and mature whole soybeans. Among the popular fermented soyfoods are soy sauce, miso, tempeh and natto.

In recent years, there has been an increasing interest in the West in exploring the food values of soyfoods. Some of them have shown great potential for being incorporated into Western diets.

Tofu

Tofu (Japanese), Dan fu (Vietnamese), Teou fu or Tou fu ho (Chinese) or bean curd is a cottage cheese-like product formed into a cake, which is precipitated from soy milk by a calcium salt or, in some instances, by concentrated sea water. Tofu can be prepared for the table in many different ways; the most important are in soup and by deep fat frying, the latter called aburage in Japanese and Yu Tou Fu in Chinese. Tofu compares with cheese or meat, it is much lower in calories because of its higher protein/fat ratio. It is also cholesterol free, lactose free and lower in saturated fat. Composition of tofu and annual per capita consumption in some countries is shown in Tables 10 and 11, respectively. The annual consumption of tofu is between 100 to 150 g in countries other than those of Asian origin. Throughout East Asia, tofu has been the most popular way to serve soybeans as a food. In 1997, tofu and tofu derivatives were dominant in China, Korea and Japan. About 60 percent of total soybean consumption in Japan corresponded to Tofu and tofu derivatives (Saio, 1999).

Germany is the most important market for tofu in the European Community, followed by United Kingdom, France and Holland (Kerntke, 1992). In India, soypanner (the Indian name for tofu) is acceptable to the consumers (Bhatnagar et al., 1991).

Table 10. Composition of tofu on wet and dry matter basis.

Table 11. Tofu annual per capita consumption.

Soybean milk

Soymilk is a water extract of soybeans, closely resembling dairy milk in appearance and composition. Soymilk contains total solids of 8 to 10 percent, depending on the water: bean ratio in its processing. Protein is about 3.6 percent; fat, 2 percent; carbohydrates, 2.9 percent and ash, 0.5 percent. Soymilk composition compares favourably with those of cow’s milk and human milk, Table 12. It contains the highest amount of protein, iron, unsaturated fatty acids and niacin, but the lowest amount of fat, carbohydrates and calcium. It is lactose and cholesterol free. Soymilk provides proteins and other nutrients to people in regions where the supply of animal milk is inadequate. It is especially important for infants and children who exhibit allergic reactions to dairy milk or have a particular need for adequate protein in their diets (Liu, 1997). Progress in reducing beany flavour by researchers at Cornell University and the University of Illinois, has made soymilk popular as a beverage in the Far East. It is steadily spreading to the Western world.

Soymilk is quite popular en China and Korea, but its consumption is insignificant in Japan (Saio, 1999). The United Kingdom is the main European market for soymilk, followed by Germany, France and Holland (Kerntke, 1992). In many other countries, soymilk is being produced and commercialized under different names, for example "A de S" in Mexico; soy-milk in India; "Soja drink" in Brazil.

Soy sprouts

Consumption of soy sprouts is large in China and Korea (14.2 percent) (Saio, 1999). In the Western world, the most common use of soy sprouts is cooked with vegetables and meat, poultry or fish. In Mexico, the main, if not the unique, dish prepared with soy sprouts is called "chop suey". In the Orient, soy sprouts are consumed cooked as vegetable or in soup. There is no consumption data available in the literature for soy sprouts.

Soy paste

Soy sauce

Among all fermented soyfoods, soy sauce is now the most widely accepted product, not only in the Far East but also in Western countries. Soy sauce is a dark-brown liquid extracted from a fermented mixture of soybeans and wheat.

Tempeh

Tempeh is one of the most popular fermented foods in Indonesia, New Guinea and Sumatra. Because of its meat like texture and mushroom-like flavour, tempeh is well suited to Western tastes. It is becoming a popular food for vegetarians in the United States and other parts of the world. Tempeh serves as a main dish or meat substitute.

Natto

Natto is one of the few products in which bacteria predominate during fermentation. When properly prepared, it has a slimy appearance, sweet taste and characteristic aroma. In Japan, it is often eaten with soy sauce or mustard. It is served for breakfast and dinner along with rice. In 1997, Japan used 122 metric tonnes of soybeans for natto manufacturing (Saio, 1999).

Vegetable soybeans

Immature green soybeans are being marketed in the United States as a frozen vegetable by SunRich (Weingartner, et al., 1999).

In the United States, six companies dominate the soyfood market. The retail values of soyfood sales in the United States are shown in Table 13. Soymilk sales increased from US$2 million in 1980 to US$207 million in 1998 and it is the fastest growing soyfood. Soy proteins and soy sauce were the most demanded soyfood during 1998; together these soyfoods totalled 70 percent of the United States soyfood sales.

Table 12. Composition of soymilk, cow’s milk and human breast milk.

Table 13. Retail value of soyfood sales in the United States during 1980 and 1998.