Tofu, also called ‘bean curd’ and ‘soybean curd,’ has come to be synonymous with vegetarian food. With its invention presumed to be in China, over 2000 years ago, tofu is a replacement for meat and high calorie-containing edibles. There exist three theories around the discovery of tofu, one of which ties tofu to the Han dynasty ruler, Liu An.
However, there is contention concerning this theory since tofu was featured in Chinese cuisine ever since the 2nd century BC.
The second theory opines that tofu was an accidental discovery, wherein slurry of boiled soybeans happened to come in contact with seawater, then considered impure, which led to its coagulation and into the jelly-like substance that is tofu.
The last theory maintains that the Chinese learned the art of curdling soy milk by emulating the process of curdling milk by the Mongolians, thus, making tofu.
It has high protein content, hardly any calories, and high mineral content, including iron. Tofu is devoid of any animal protein.
Tofu is made from a soy milk coagulation using certain salts or enzymes. It is made by coagulating soy milk or freshly prepared soy milk using coagulating agents. These include calcium sulfate or gypsum, magnesium chloride, calcium chloride, or acid coagulant like glucono delta-lactone, or enzyme coagulant called papain. Like the curdling of milk, soy milk also gets curdled and results in an almost jelly-like substance with high moisture content. There are broadly two kinds of tofu: silken or soft tofu and firm tofu.
Silken tofu is higher in moisture content. It is allowed to coagulate within its packaging; hence, it can retain its moisture. Firm tofu, however, is drained of its moisture before it is packed. It is placed between wooden blocks that squeeze the water out of it over a period of time. It can be white or a light shade of red, depending on the coagulant used.
Tofu has a very subtle to almost no taste, even if processed using enzymes. It can absorb the flavor of the spices and the vegetables it is cooked alongside.