Tofu is
a highly versatile and nutritious food that is made from soybean curds. Although the word "tofu" is Japanese, the
food seems to have originated in ancient China, where the Mandarin term is "doufu." The creation of tofu is generally
attributed to the ruler Liu An of Huai-nan during the second century B.C. The creation of tofu was
probably accidental. Although soybeans are not technically a grain, the Chinese considered the soybean one of their essential
Five Sacred Grains, along with rice, wheat, barley, and millet. It is likely that Liu An prepared soybeans in much the same
way as grains, by drying, mashing, and boiling. The addition of sea salt would not only have seasoned the puree, it would
have also acted as a solidifying agent, forming curds. Another theory suggests that the curding process was simply imported
from neighboring regions. Regardless, soybeans appear to have been processed into tofu by the second century B.C.
using a sea water precipitate to solidify the tofu, a process still used by many manufacturers. According to ancient text, soybeans were cultivated in northern China at least as early
as the 15th century B.C. , during the Chang period. A sixth century Chinese encyclopedia of agriculture,
the first of its kind, cites that the explorer Choken brought back soybeans to China from his expeditions to Greece, Rome,
and India. However, according to legend, the soya plant was cultivated centuries earlier. In 2838 B.C. ,
the emperor Sheng-nung wrote a treatise on plants which describes the soya plant in detail. Chinese agricultural experts in
2207 B.C. also wrote about soybean cultivation. Clearly, soybeans were an important staple crop
in China for quite some time. The soybean was also recognized for its regenerative properties: the roots of soybeans contain
nodules, which discharge nitrogen, and thereby enrich the soil. This important quality made its mark on the old ideogram for
the soya plant "su," which contained little lines to symbolize roots. During the eighth century, Chinese Buddhist missionaries introduced the soya plant to Japan and Korea, although
they may have been used there much earlier. Buddhist monks believed that a vegetarian diet was healthier for the spirit so
they advocated eating the protein-rich tofu as an alternative to meat. First the upper classes of Japan adopted tofu into
their diets and by 1400, during the Muromachi period, tofu was popular among all classes in Japan. Until about World War II most Japanese and Chinese tofu was made in small family-run shops,
each of them using the same ingredients, methods, and tools. In the 1960s, the Japanese Food Research Institute made recommendations
for modernizing and standardizing tofu production throughout the nation. Their suggestions included using calcium sulfate
as the thickening agent, rather than the natural sea water precipitate, nigari. They also recommended using pressure cookers
to speed the process. Hydraulic presses and centrifuges replaced manual lever presses and hand-turned screw presses. Higher
speed grinders and aluminum boxes replaced the original wooden boxes. Despite the improvements in efficiency and productivity,
many believed that the new methods compromised the flavor of tofu. Traditionalist manufacturers still retain much of the old-style
tofu production. The ingredients for making tofu are few.
They include the milk of soybeans, water, and coagulating agents. The modern tofu manufacturing process is largely an automated
version of the traditional hand method. In the U.S., Americans
did not readily adopt soybeans into their diet. They were available by the mid-1700s and popularized by Chinese immigrants
traveling to California during the Gold Rush of the mid-1800s. As the Chinese immigrants later traveled to other parts of
the country, they spread the recipe for tofu. The demand for tofu and other Asian foods also increased after World War II
as military personnel returned from Asia, some with Asian spouses. By the 1900s soybeans were grown as a cash crop—primarily
for regenerating the soil during crop rotation—as animal feed, and for producing oil and oil-cake residue for manufacturing
purposes. By the 1950s the U.S. rivaled Asia in its production of soybeans. Forty years later, the U.S. would become the largest
soybean producer in the world, providing about two-thirds of the global supply. During the 1970s, with the growing popularity of ethnic foods in the U.S., mainstream grocers began to offer
products like tofu. At the same time, the price of meat soared, and tofu finally caught on as a popular substitute for meat,
since tofu is high in protein and low in saturated fat. The increasing health-consciousness of the U.S. populace also contributed
to the popularity of tofu. Twenty years later the tofu industry grew to more than a 4-million-pound industry.
Tofu is used in a variety of ways: as a
meat substitute, an additive to entrees, a dessert base, and a liquid base for sauces, dips, and healthful shakes.
The Soybean
The soybean is perfectly balanced in the major food categories of protein, fat, and carbohydrates
as well as in vitamins, and minerals. Soybeans also contain an ideal amount and combination of amino acids that are necessary
for assimilating nutrients by the human body. The scientific name for the
soybean is Glycine max, and it is part of the botanical family Leguminosae. The soya plant has a slightly woody stalk and
reaches a height of 30-36 inches (76-91 cm). The entire plant is covered in greenish hair. The leaves grow in groups of three
and fall off as the beans mature. The soya plant produces papilionaceous (butterfly-shaped) flowers that are either white,
red, or purple. The pods grow from 1-2 inches (2.5-5 cm) in length, each holding two or three seeds, which become soybeans.
Soya seeds are either round or oval and are similar in size to peas. Their color is usually yellow but they may also be green,
purple, brown, or a mixture of colors. Soybeans are pulses, that is, the plant has a symbiotic relationship with the bacteria,
called rhizobia, that emit nitrogen through nodules in the soya plant's roots. The
soya plant may grow as far north as 52 degrees latitude, even though it is really a sub-tropical plant. Each climate requires
slight alterations for growing soybeans, but in general, the beans are sown in the middle of May with heavy machinery. As
the beans ripen, the soya leaves fall off. After the short growing period of 15 weeks, only the stalks and pods remain. The
plants are harvested mechanically.
