Soya bean oil (also known as soybean oil) is one of the world's most widely consumed vegetable oils, extracted from the seeds of the soybean plant, Glycine max, a legume belonging to the Fabaceae family. The soybean is native to East Asia, with evidence of cultivation in China dating back over 5,000 years. The plant was considered one of the five sacred grains (wu gu) in ancient Chinese agriculture, alongside rice, wheat, barley, and millet. The scientific name Glycine max was established by the Swedish botanist Carl Linnaeus, with Glycine derived from the Greek glykys (sweet).
Soybeans are now cultivated on every continent except Antarctica, with the largest producers being Brazil, the United States, Argentina, China, and India. Global soybean production exceeds 370 million metric tonnes annually, with approximately 28 million metric tonnes of soybean oil produced each year — making it the second most produced vegetable oil in the world after palm oil. The soybean thrives in temperate climates with warm summers, adequate rainfall, and fertile, well-drained soils.
The production of soybean oil begins with the harvesting of mature soybeans, which contain approximately 18-20% oil by weight. After cleaning and conditioning, the beans are cracked, dehulled, and flaked to increase surface area for oil extraction. The primary extraction method is solvent extraction using food-grade hexane, which efficiently removes oil from the flaked soybeans.
The resulting crude soybean oil undergoes degumming (to remove phospholipids or lecithin — itself a valuable co-product), neutralisation, bleaching, and deodorisation to produce fully refined soybean oil. The defatted soybean meal, containing approximately 44-48% protein, is the world's most important protein source for animal feed.
Soybean oil has a distinctive fatty acid profile characterised by a high proportion of polyunsaturated fatty acids: approximately 51-54% linoleic acid (omega-6), 7-10% alpha-linolenic acid (omega-3), 22-25% oleic acid, 10-12% palmitic acid, and 4-5% stearic acid. This composition gives soybean oil excellent nutritional properties — it is one of the few common vegetable oils that provides significant amounts of both omega-6 and omega-3 essential fatty acids.
Historically, soybeans were primarily cultivated for their protein content in East Asian cuisines, used to produce tofu, soy sauce, tempeh, miso, and soy milk. Large-scale extraction of soybean oil began in the early 20th century, first in Manchuria (northeastern China) and subsequently in the United States, where soybean cultivation expanded dramatically during and after World War II. By the 1960s, soybean oil had become the dominant vegetable oil in the American food supply.
In the food industry, refined soybean oil is used extensively in cooking oil blends, salad dressings, mayonnaise, margarine, shortening, baked goods, snack food frying, and as a general-purpose food manufacturing ingredient. High oleic soybean varieties and interesterified soybean oil products now provide improved stability without trans fat formation.
Soybean oil also has significant industrial applications. It is a major feedstock for biodiesel production — soybean methyl ester (SME) is the primary biodiesel fuel in the United States and Brazil. Soybean oil is used in the manufacture of printing inks (soy ink is widely used in newspaper and commercial printing), paints and coatings, plasticisers, adhesives, hydraulic fluids, and bio-based polymers. Epoxidised soybean oil (ESBO) is an important plasticiser and stabiliser in PVC manufacturing.
Soybean lecithin, extracted during the degumming stage of oil refining, is one of the most important food emulsifiers globally, used in chocolate, baked goods, instant foods, infant formula, and numerous processed food applications. It is also widely used in pharmaceutical and industrial applications.
Food-grade improvements include the development of low-linolenic soybean varieties that improve oil stability without hydrogenation, non-GMO identity-preserved supply chains for markets requiring non-GMO certification, and organic soybean oil production to meet growing consumer demand. Modern refining techniques have also reduced the formation of process-induced contaminants and improved the overall quality and consistency of refined soybean oil.
Interesting facts about soybean oil include: the soybean is the world's most important oilseed by production volume; soy ink was first developed in the 1970s as an alternative to petroleum-based inks; soybean meal provides approximately 70% of the world's protein meal for animal feed; Henry Ford was an early proponent of industrial soybean uses, incorporating soy-based plastics into automobile parts in the 1940s; and soybeans fix atmospheric nitrogen through root nodule bacteria, reducing fertiliser requirements and benefiting subsequent crops in rotation systems.