Tofu, also known as soybean curd, is a soft, cheese-like food made by curdling fresh hot soymilk with a coagulant. Traditionally, the curdling agent used to make tofu is nigari, a compound found in natural ocean water, or calcium sulfate, a naturally occurring mineral. Curds also can be produced by acidic foods like lemon juice or vinegar. The curds then are generally pressed into a solid block.The production of tofu from soy milk is similar to the production of cheese from milk (fermentation), although some tofu is made by processing non-soy products, such as almonds or black beans.
Two major byproducts of the process are tofu skin and soy pulp.
Tofu is low in calories, contains beneficial amounts of iron (especially important for women of child bearing age) and has no cholesterol. Depending on the coagulant used in manufacturing, the tofu may also be high in calcium (important for bone development and maintenance), and magnesium (especially important for athletes).
Types of fresh Tofu
- Firm tofu is dense and solid and holds up well in stir fry dishes, soups, or on the grill… anywhere that you want the tofu to maintain its shape. Firm tofu also is higher in protein, fat and calcium than other forms of tofu.
- Soft tofu is a good choice for recipes that call for blended tofu, or in Oriental soups.
- Silken tofu is made by a slightly different process that results in a creamy, custard-like product. Silken tofu works well in pureed or blended dishes. In Japan, silken tofu is enjoyed "as is," with a touch of soy sauce and topped with chopped scallions.
- Tofu is rich in high-quality protein.
- It is also a good source of B-vitamins and iron.
- When the curdling agent used to make tofu is calcium salt, the tofu is an excellent source of calcium.
- While 50 percent of the calories in tofu come from fat, a 4-ounce serving of tofu contains just 6 grams of fat. It is low in saturated fat and contains no cholesterol. Generally, the softer the tofu, the lower the fat content.
- Tofu is also very low in sodium, making it a perfect food for people on sodium-restricted diets.