About 85 percent of the world’s soybean crop is processed into meal and vegetable oil, and virtually all of that meal is used in animal feed. Some two percent of the soybean meal is further processed into soy flours and proteins for food use.
Approximately six percent of soybeans are used directly as human food, mostly in Asia.
The oil component of crushed soybeans is primarily used for human consumption, although the proportion used for biodiesel production is growing rapidly, especially in the U.S.
Food uses of soybeans include traditional soyfoods such as tofu and soymilk as well as 20th century innovations – meat analogs and soy-based yogurts, for example. For more information about soyfoods, please visit our Soyfoods Facts page.
Soy ingredients have become staples in the food manufacturing industry. Lecithin is widely used as an emulsifier; since the 1970s, partially hydrogenated soybean oil has been a mainstay in the production of snacks, baked goods, salad dressings and other foods soy protein ingredients play functional roles in baked foods, processed meats and other products.
In addition to being used for their functional characteristics, soy ingredients are used to add nutrition to processed foods; some isolated soy proteins, for instance, are specifically designed to be used in acidic or clear beverages – products that could not, until recently, be protein-fortified.
Soybeans are also processed into many industrial products. The primary one at this time is biodiesel, or soy methyl esters, which may be used in any diesel engine (see also our Biodiesel Facts page). In addition, soybeans are processed into hydraulic oil, grease, solvent, ink, plastics and other products.
Common Processing Methods
After being cleaned and dehulled, one of three processes is used to separate the soybean oil from the protein meal (this is also called "crushing" or "oil mill" operations).
These processes are:
- Solvent extraction: This process, which is the one used most commonly around the world, uses hexane to leach or wash (extract) the oil from flaked oilseeds. This method reduces the level of oil in the extracted flakes to one percent or less.
- Continuous pressing: This process is performed at elevated temperatures, using a screw press to express the oil from ground and properly conditioned soybeans. The pressed cake is reduced to between 4 percent and 6 percent oil content by this method.
- Hydraulic or batch pressing: This is an intermittent pressing operation carried out at elevated temperatures in a mechanical or hydraulic press after the soybeans have been rolled into flakes and properly conditioned by heat treatment. It is the oldest known method of processing oilseeds.