Groundnut oil

Refined peanut oil is degummed, neutralised, bleached and deodorised, which strips its colour and flavour and removes most of its protein, resulting in a neutral, high-smoke-point oil. Many people with a peanut allergy tolerate highly refined oil, but traces of protein can remain, and EU law requires peanut oil to be labelled as a peanut allergen however it is refined; anyone with a peanut allergy should follow their allergist's advice. Cold-pressed peanut oil retains more nutrients and subtle peanut flavor through mechanical extraction without heat. Roasted or gourmet peanut oil is made from roasted peanuts, delivering an intense, aromatic character prized in Asian cuisines. High-oleic peanut oil, developed from specially bred cultivars, contains up to 80% oleic acid compared to 41-67% in regular varieties, offering superior oxidative stability and extended frying life.

The peanut's journey began in the valleys of South America, likely southern Bolivia and northwestern Argentina, where indigenous peoples cultivated it for thousands of years. Spanish and Portuguese traders carried peanuts to Africa, Asia, and Europe during the 16th century colonial expansion. Peanut oil became a significant industry in the 19th century, when Marseille's mills began crushing groundnuts imported from Senegal and the Gambia in the 1840s; by 1912 the city was crushing over 360,000 tonnes a year. The oil gained American prominence during World War II when shortages of other cooking fats drove demand. A pivotal moment came at the 1900 Paris Exposition Universelle, where the Otto Company ran a diesel engine on peanut oil—one of the first public demonstrations of vegetable oil as engine fuel. George Washington Carver championed peanut oil's potential, advocating for domestic production when the U.S. was importing roughly 5 million litres annually. Today, China is by far the largest producer, accounting for roughly 40–50% of world output of about 5–6 million tonnes a year, followed by India and Nigeria.

Peanut oil's exceptional frying performance stems from its unique fatty acid composition: approximately 50% monounsaturated oleic acid, 30% polyunsaturated linoleic acid, and 20% saturated fats. This balance creates remarkable oxidative stability—the saturated and monounsaturated fats resist breakdown while the relatively low polyunsaturated content minimizes harmful free radical formation during heating. The smoke point of around 230 °C for refined oil represents the temperature at which triglycerides decompose into glycerol and free fatty acids, producing visible smoke and acrolein. High-oleic varieties push this stability further, with oleic acid concentrations near 80% reducing the formation of polar compounds and polymers that degrade oil quality. The Maillard reaction and caramelization proceed optimally in peanut oil's temperature range, creating the golden-brown crust and complex flavors that define superior fried foods. Tocopherols naturally present in the oil act as antioxidants, scavenging free radicals and extending both shelf life and frying longevity.

Peanut cultivation presents a relatively favorable environmental profile compared to other oilseed crops. Published life-cycle estimates of peanut oil's carbon footprint vary widely with growing region, yields and processing, so it cannot be ranked reliably against other oils such as rapeseed. As a nitrogen-fixing legume, peanuts reduce the need for synthetic fertilizers and can improve soil health in crop rotation systems. However, concerns exist around water usage in drought-prone growing regions and the consolidation of production in developing nations where labor practices vary. Consumers seeking ethical options can look for Fairtrade-certified peanut products and the EU organic leaf, although certified peanut oil is still uncommon on shelves. Major producers are increasingly implementing traceability systems and sustainable farming initiatives, with goals toward supply chain transparency and water-positive operations.