Tofu is made from soymilk curdled with a coagulant, usually nigari (magnesium chloride) or gypsum (calcium sulfate). Similar to bland, firm, custard, tofu takes on the flavor of any seasonings. It is high in protein and (if made with calcium sulfate) calcium, and contains vitamins B complex, vitamin E and phytoestrogens (which may ease menopausal symptoms and may have a protective effect against prostate and reproductive cancers).
The now-familiar white block of soy curd is one of the most versatile ingredients in the natural foods pantry. There are essentially three varieties of tofu with regard to texture. Firm, extra-firm, and silken tofu are the most commonly available. Try firm and extra-firm tofu by cutting it into chunks and adding cooked to a meatless stir-fry. These firm varieties may be grilled, sautéed, and broiled because they hold up well to handling. Marinate cooked firm tofu in flax seed oil and lemon juice in the refrigerator overnight; then toss with chopped vegetables for a salad.
Tofu is made from soy milk and then turned into curds and whey just as Western cheeses are made, except that the latter are usually coagulated by means of rennet, which is extracted from animals. Tofu is curdled by means of a “salt”; either calcium sulfate (gypsum) used in China or Nigari, bittern, derived from the sea (magnesium chloride, plus other salts and trace elements). Or less desirably, tofu can be coagulated with lemon juice or vinegar.