Soy milk (also called soya milk, soymilk, soybean milk, or soy juice and sometimes referred to as soy drink/beverage) is a beverage made from soybeans. A traditional staple of Asian cuisine, it is a stable emulsion of oil, water, and protein. It is produced by soaking dry soybeans and grinding them with water. Soy milk contains about the same proportion of protein as cow's milk: around 3.5%; also 2% fat, 2.9% carbohydrate, and 0.5% ash. Soy milk can be made at home with traditional kitchen tools or with a soy milk machine. Despite the terminology used by consumers, it is illegal to sell soy milk under that name in the European Union, where - with certain exceptions - EC Regulation (1898/87) has restricted the term 'milk' to mammary secretions since 1987; in such countries the term 'soy drink' is commonly used.[1][2]
The coagulated protein from soy milk can be made into tofu, just as dairy milk can be made into cheese.
Preparation of soya milk
Soy milk can be made from whole soybeans or full-fat soy flour. The dry beans are soaked in water overnight or for a minimum of 3 hours or more depending on the temperature of the water. The rehydrated beans then undergo wet grinding with enough added water to give the desired solids content to the final product. The ratio of water to beans on a weight basis should be about 10:1. The resulting slurry or purée is brought to a boil in order to improve its nutritional value by heat inactivating soybeantrypsin inhibitor, improve its flavor and to sterilize the product. Heating at or near the boiling point is continued for a period of time, 15–20 minutes, followed by the removal of an insoluble residue (soy pulp fiber or okara) by filtration.
There is a simple yet profound difference between traditional Chinese and Japanese soy milk processing: the Chinese method boils the filtrate (soy milk) after a cold filtration, while the Japanese method boils the slurry first, followed by hot filtration of the slurry. The latter