Bean curd, sometimes called "soy cheese" and most often called "tofu," has been a staple of Asian diets for well over 1,000 years. Despite its longevity, the way it is made has not changed much over the years, even though most tofu is now made in factories. Health claims about tofu are currently inconclusive, and soy-sensitive individuals should probably avoid ingesting it.
Bean curd, or tofu, does not have an exact date of origin. The earliest known mention of it as a product occurred in the year A.D. 950, in China. Four separate origin stories have circulated about its discovery, but not much evidence exists to support any of them, so its exact origins remain unclear. The word “tofu” is Japanese, and the product itself is a popular source of protein all over Asia. It has grown in popularity around the world, particularly with the rise in popularity of vegetarian and vegan diets.
How It Is Made
Although much of the world's tofu is made in factories, the process is similar to how it was originally made. Soy beans are soaked in water and mashed to create soy “milk.” A coagulant is then added in order to curdle the milk. The curds are drained and pressed into molds, often at the same time. Nigari is a traditional coagulant, though calcium sulfate or gypsum may also be used. This process can be performed at home to create fresh tofu, for interested parties.
Tofu is full of soy protein, and may also contain high amounts of calcium if it was made with calcium sulfate. Exact nutritional content varies by manufacturer recipe, and can be found on commercial tofu packaging. Tofu also contains isoflavones, which have been touted as having numerous positive health effects. Cancer inhibition, lowering of bad cholesterol, and reversal of osteoperosis are just some of the benefits that isoflavones allegedly cause. According to the Linus Pauling Institute at Oregon State University, research is currently limited and/or inconclusive regarding these claims as of June 2010.
In addition to the different coagulants used to create tofu, the end product comes in two basic types: regular and silken. Regular tofu is sold in liquid, inside tubs. Silken tofu is sold in aseptic packaging, which stays shelf-stable for longer periods of time and is nonperishable until it is opened. Both types of tofu are available in varying firmness levels, from soft to extra-firm.
Individuals who are sensitive to soy and soy products should avoid ingesting tofu or tofu-related products. Since it is unclear whether soy sensitivities stem from soy itself or some of the processes involved in creating soy products, some soy-sensitive individuals may not experience problems with tofu, as the soy involved is minimally processed.