Tofu, made from soybeans, which are known as "plant meat," originated from Bagong Mountain in Anhui, China, and has a history of over 2,000 years. Tofu is highly nutritious, which is why some jokingly call it the "fifth great invention" of ancient China, in addition to the Four Great Inventions. The varieties of tofu are五花八门
A simple, square piece of tofu can be a small cold dish at home or a main course in a large restaurant. There are even restaurants specializing in tofu, such as the Huaiyang Tofu Banquet. The varieties of tofu are also五花八门. In addition to traditional northern tofu and southern tofu, many "technologically advanced" tofus have emerged in recent years, such as lactone tofu, mianmian tofu, and silk tofu. There are even fresh red strawberry tofu, green vegetable juice tofu, and nutritious tofu with peanuts added. Different types of tofu have different nutritional values
Associate Professor Zhihong Fan from the College of Food Science and Nutritional Engineering at China Agricultural University told a reporter from the Life Times that traditional Chinese tofu is made by soaking soybeans in water until they swell and soften, then grinding them into soy milk. The soy milk is then "curdled" with bittern or gypsum to cause the dispersed protein particles to coagulate. Today's market mainly offers northern tofu, southern tofu, lactone tofu, and "fake tofu."
Northern Tofu. Also known as old tofu, it is generally curdled with bittern (magnesium chloride). It is characterized by its firm texture, strong elasticity, low water content, and a "coarse" taste that is slightly sweet and bitter. It has the highest protein content and is suitable for frying, making fillings, etc. Although northern tofu has a slightly bitter taste, it has higher levels of magnesium and calcium, which can help lower blood pressure and vascular tension, prevent cardiovascular diseases, and strengthen bones and teeth.
Southern Tofu. Also known as soft tofu or tender tofu, it is generally curdled with gypsum (calcium sulfate). It is characterized by its delicate texture, elasticity, high water content, and a sweet and fresh taste. Its protein content is over 5%. It is suitable for cooking methods such as mixing, stir-frying, stewing, quick-boiling, braising, and making soups.
Lactone Tofu. It abandons the traditional bittern and gypsum and uses glucono-delta-lactone as a coagulant, adding substances like trehalose and plant gum to retain water. Although its texture is fine and its mouthfeel is tender and smooth, it is not as nutritious as traditional tofu. This is because, firstly, the soybean content is less, so it doesn't taste like tofu. Secondly, the calcium and magnesium in tofu mainly come from gypsum and bittern, while the glucono-delta-lactone coagulant used today contains neither calcium nor magnesium, thus reducing its nutritional value.
"Fake Tofu". Readers will easily find many "fancy tofus" on the market: Japanese tofu, almond tofu, milk tofu, egg tofu, etc. Although they are all called "tofu," they are watery, white, and tender with a smooth texture, but they have nothing to do with tofu. This is because these "tofu products" do not contain soybeans at all. For example, Japanese tofu is actually "egg tofu" made by coagulating a colloidal solution of eggs.
How to Choose Tofu
How should one choose tofu? Zhihong Fan teaches us a few tips. First, the color of the tofu should be slightly yellowish; if it is unnaturally white, it may have been bleached and should not be purchased. Second, good boxed lactone tofu should have no gaps in the box, a flat surface, no bubbles, no water leakage, and no晃动感 when shaken. A faint soybean aroma should be noticeable when the box is opened. Third, tofu is a high-protein food and spoils easily, so it is best to buy it from a place with good refrigeration. Fourth, after buying it, soak it in water immediately and refrigerate it. Take it out to cook within 4 hours to keep it fresh.