You can buy various types of tofu: the difference lies in the way in which the soya milk is curdled. If it is done by adding calcium sulphate, you will get a tofu rich in calcium, excellent for preventing osteoporosis. If the curdling is achieved through the addition of other substances, such as Nigari or magnesium chloride, or with lemon juice, you will get an equally high-protein food, less rich in calcium but with a more velvety consistency.

Tofu is a high-protein food obtained by curdling soya milk. The process is analogous to that which is used to get cheese from cow’s milk. Tofu, a Japanese word even though this "invention" is purely Chinese, is widely used in vegetarian cooking and particularly for vegan dishes.