Soybeans enjoy having their own privileged class. They are unique with an amazing protein content of 34 percent, one of the highest of all foods (compare that to meats that range from 15 to 22 percent). Yet, we hardly ever eat them. Even though they are an impressive source of protein, they have flunked the palatability test in every country anyone every tried to introduce soybeans as a staple. But all those soybeans are not wasted.
We use its oil either directly or indirectly in all kinds of consumables goods. The soybean protein is a prime animal feed, but it also provides a significant protein source in its many permutations for vegetarians.
Interestingly enough, soybeans are a very recent introduction to U.S. agriculture, yet in a few decades they have become her single largest cash crop. Although we don’t eat them either fresh or in dry form as we do other legumes, we consume plenty of them in other ways. Most of us have never had a bag of soybeans in our kitchen cupboards, yet we recognize the coagulated or fermented products derived from them.
Foods from the soybean
There are five soybean-derived foods (excluding oil) that you come across on many supermarket shelves. They were virtually unknown in North America in the 1940s and 1950s.
Two of these became fairly common: soy sauce (and its cousin tamari sauce) now in nearly every kitchen and tofu. The other three are not so well known: soy milk, tempeh and miso. Tofu and soy milk are unfermented, soy sauce, tempeh and miso are fermented products. The Chinese have been using fermented soybean products for at least 2200 years.
Tofu is soybean curd, very similar to unripened cheese curd both in flavor (they both have none) and the way they make them. First they soak the dry soybeans overnight. Then they crush and cook these lightly hydrated but still hard beans until they turn into a mush. After filtering off the liquid, which is the soy milk, they add calcium or magnesium salt to coagulate the curd. They put this semisoft solid into wooden forms and press it for several hours to squeeze more of the liquid whey out.
Starting with 4 pounds (4 kg) of dry soybeans they end up with about 6 pounds (6 kg) of tofu (the increased weight is water) plus the whey that they discard. Tofu is an ideal medium for bacterial growth and spoils very quickly at room temperature. That is no problem in the Orient where they eat tofu the same day they make it. The American food distribution system requires far longer shelflife than one day, so processors pasteurize tofu and seal it in a package for weeks of shelflife like they do cheeses.
Tofu comes in different textures from very soft, smooth, fragile, silken cakes to hard, solid, almost cheese-like bricks. The difference is in the amount of whey left in it. Soft tofu is about 85 percent, while the hard stuff is only 50 or 60 percent water. Hard tofu, often flavored with sugar, tea and spices, is the preferred form in many parts of China. Elsewhere, soft tofu or an in-between consistency is more popular.
By itself, tofu is bland and flavorless, virtually unpalatable. But it adds great texture to foods. It acts like a sponge for flavor compounds, so it takes on flavors from all other ingredients. It is good in soups, salads and stir-fries. It is suitable to marinate, to bake, to braise or to sauté just like meat. My recommendation to you is to try it at least once, no matter how reluctant you feel about tofu. For instance, why not marinate tiny tofu squares in an intense
Oriental sauce for a few hours, then add them to your salads. Wow!
Tofu is now available commercially in different flavors and forms that replicate meat (called value-added products)-tofu burgers, baked teriyaki and barbecued tofu, cutlets of tofu in marinade, tofu blocks marinated in Italian, Thai or Oriental flavors, or whatever the trend of the moment happens to be. Although plain tofu is inexpensive, these value-added products are not cheap. You will probably pay almost as much for them by weight as for medium to high-priced meats.
The protein content of tofu is not very high, only about 7 percent, because of the large amount of diluting water it contains. The harder the tofu is, the less water and more protein concentration in a same-weight piece. A 4-ounce (113-g) tofu, in dietitians’ language, contains 8 to 10 grams of protein.
Soy milk the other unfermented soy product, is the liquid that results from the first step of the tofu-making process. However, more cooking and processing are necessary before the liquid becomes suitable and acceptable to drink as soy milk. The processor adds salt, sweetener, oil and flavoring to give it a little taste. Without them, it tastes like plain tofu, very blah!
Soy sauce is to Orientals what ketchup is to Americans. Each country, and even districts within country, has its own ways of making it and each one may be very different from the other. Soy sauce has become very popular in our kitchens, too.
To make Japanese soy sauce, the processor cooks the soybeans and adds roasted, and coarsely crushed wheat berries. The ratio of the two differs in every region. Then the processor inoculates the mash with a specific mold (Aspergillus) and lets this mixture mature for about 3 days under controlled temperature and humidity conditions to develop enzymes. After that he adds a brine solution to destroy the mold. The result, moromi mash, is what ferments and ages in fermentation tanks at natural temperature for about 2 years.
Fermentation for our domestically produced soy sauce is only about 6 months but under controlled temperature.
During the fermentation, two processes take place. In the first one the proteins of the soybeans are broken down into their component amino acids, and in the second the
carbohydrates of the wheat kernels change to sugar. The brine is also part of the process.
It introduces saltiness and triggers a new set of chemical reactions between the amino acids and sugar. A yeast fermentation runs simultaneously with these changes that alters part of the sugar into alcohol, introducing a tart flavor component. The result is a further deepening of flavor with even more complexity and the development of a rich, clear color.
Aging follows fermentation and the two processes take 6 months to a year, after which they filter off the reddish-brown syrupy mash under pressure to squeeze out every single drop. Then they pasteurize the liquid before bottling to get rid of any remaining live culture.
Chinese soy sauce is somewhat different. They make it without wheat and is both thicker and heavier than the Japanese variety. The Chinese add molasses to give sweetness and a dark color.
Tamari is similar to the Japanese-style soy sauce but has little or no wheat, is darker, heavier and stronger-flavored than soy sauce. Salt makes up a very high 15 to 20 percent of any soy sauce, so don’t use it too generously. It generally replaces table salt in recipes.
Tempeh is a close relative to tofu. Tofu is unaged and unfermented. Tempeh is also unaged, but it is fermented for a day under warm, humid conditions with inoculated mold culture so it develops a mild flavor. Otherwise, it is a white cake-like food similar to tofu. Tempeh originated in Indonesia and because it is more tasty than tofu, it is popular with vegetarians as a meat substitute.
You can buy tempeh in health food stores flavored with seaweed, soy sauce, five-spice or just plain sea veggies. Sometimes they fortify it with extra cooked soybeans. It has the same protein content as tofu (about 7 percent) unless has the benefit of added soybeans. That boosts the protein content up to a respectable 21 percent (24 grams in a 4-ounce or 113-g serving)
Miso is a Japanese fermented product that begins with soaked soybean mush into which they mix either pre-fermented soybeans, rice or barley. The processor inoculates this conglomeration with mold, and ferments it for a few days. Then he blends, mashes and pasteurizes the mush, and it is ready for sale in sealed jars or in bulk in health food stores.
In bulk it is like thick porridge. It has a complex, distinctive taste which makes it good for flavoring and as a soup base. The cost is about the same as a medium-priced meat. The protein content is around 13 percent (15 grams in a 4-ounce or 113-g serving) depending on what other ingredients they have added.
