Tofu, made from soybeans known as "vegetable 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, alongside the other four.
The varieties of tofu are incredibly diverse
A simple, square block of tofu can be a small home-cooled dish or the main course in a large restaurant. There are even restaurants specializing in tofu, such as the Huaiyang Tofu Banquet. The variety of tofu is also extensive. In addition to traditional northern and southern tofu, many "technologically advanced" types have emerged in recent years, such as lactone tofu, mianmian tofu, and silk tofu. There are even strawberry tofu, which is bright red; vegetable juice tofu, which is emerald green; and nutritional tofu with added peanuts. Different types of tofu have different nutritional values
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 features several categories of tofu: 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 firmness, strong texture, low water content, and a "coarse" taste that is slightly sweet and slightly bitter. It has the highest protein content and is suitable for frying, braising, and making fillings. Although northern tofu has a slightly bitter taste, it is higher in 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 fine texture, elasticity, high water content, and sweet, fresh flavor, with a protein content of 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 in favor of glucono-delta-lactone as a coagulant, and adds substances like trehalose and plant gum to retain water. Although it has a delicate texture and a tender, watery mouthfeel, it is not as nutritious as traditional tofu. This is because, firstly, the soybean content is lower, so it doesn't taste much like tofu. Secondly, the calcium and magnesium in tofu mainly come from gypsum and bittern. The glucono-delta-lactone coagulant used today contains neither calcium nor magnesium, thus reducing its nutritional value.
"Fake tofu". Readers will不难发现 (不难发现 -不难发现) that there are many "novelty tofus" on the market: Japanese tofu, almond tofu, milk tofu, and egg tofu. Although they all share the name "tofu," they are all moist, white, and tender with a smooth texture, but they have no connection to tofu at all. This is because these "tofu products" do not contain soybeans as an ingredient. For example, Japanese tofu is actually "egg tofu," made by coagulating a colloidal solution of eggs.
How to choose tofu
How should you choose tofu? Fan Zhihong teaches us a few tips. First, tofu should have a slightly yellowish tint; if it is unnaturally white, it may have been bleached and should be avoided. Second, good boxed lactone tofu should have no gaps in the box, a flat surface, no bubbles, no water leakage, and no sloshing when shaken. It should have a faint soy aroma when opened. Third, tofu is a high-protein food and spoils easily, so it's 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 and cook it within 4 hours to keep it fresh.