Oil

A substance encompassing lipids from plants and animals and mineral hydrocarbons, central to food, fuel, and industrial raw materials.

Oil

Overview

Oil (油) is a general term for hydrophobic (lipophilic) substances that do not mix well with water and exist as liquids at room temperature. It is broadly divided into lipid-based oils obtained from plants and animals (edible oils and fats) and mineral oils mined from the earth's crust (petroleum and mineral oil). Humanity has used oil as food, lighting, fuel, lubrication, and chemical feedstock, and today it is a foundational resource supporting the entire food, energy, and chemical industries.

Main Content

Chemical definition and classification

Lipid-based oils are mainly composed of triglycerides (a structure in which three fatty acid molecules are bonded to one glycerol molecule). Depending on the carbon chain length and presence of double bonds, fatty acids are classified as saturated, monounsaturated (MUFA), and polyunsaturated (PUFA), and omega-3, -6, and -9 families are named by double-bond position. The more double bonds, the more likely the substance is liquid at room temperature (oil); the higher the saturation, the closer it is to solid (fat).

Petroleum-based oil is a mixture of hydrocarbons (alkanes, cycloalkanes, aromatics), separated by carbon number and boiling point into LPG, gasoline, kerosene, diesel, heavy fuel oil, and asphalt. Refining goes through atmospheric distillation, vacuum distillation, cracking, and reforming processes.

Edible oils

Soybean oil, canola oil, olive oil, sesame oil, perilla oil, sunflower oil, palm oil, coconut oil, and others are representative. Extraction methods are divided into physical pressing (cold press) and solvent (hexane) extraction, followed by refining processes of degumming, deacidification, bleaching, and deodorization. Smoke point (the temperature at which smoke begins to appear) is a criterion for choosing a cooking method, and olive oil is graded (extra virgin, etc.) by acidity and phenol content.

Industrial oils

Lubricants, cutting fluids, transformer oils, and hydraulic fluids manage friction and heat in machinery and power equipment. Biodiesel and HVO (hydrotreated vegetable oil) made from waste cooking oil and oilseed crops, and sustainable aviation fuel (SAF), are attracting attention as decarbonized fuels. In addition, they are widely used as raw materials for paints, inks, soaps, cosmetics, surfactants, and pharmaceuticals.

History

In ancient Egypt and Greece, olive oil was used for food, lighting, and beauty, while in East Asia, sesame oil and perilla oil were central to lighting and cooking. In the 19th century, whale oil handled industrial lighting, but with the 1859 development of the Titusville oil well in Pennsylvania, USA, the petroleum era began. In the 20th century, as oleochemical and refining technologies developed, mass production of edible oils and the hydrogenated oil (margarine) industry expanded.

Health and nutrition

Oil is a high-energy nutrient providing about 9 kcal per gram, and is essential for absorption of fat-soluble vitamins (A, D, E, K), cell membrane composition, and hormone synthesis. Linoleic acid and alpha-linolenic acid cannot be synthesized in the body and are classified as essential fatty acids. On the other hand, intake of trans fats and excessive saturated fat raises the risk of cardiovascular disease, leading countries to strengthen labeling and use restrictions.

Environment and sustainability

Major environmental issues include tropical rainforest destruction from palm oil cultivation, marine oil spills, and improper disposal of waste cooking oil. The use of waste cooking oil as biofuel feedstock and certification of deforestation-free supply chains (such as RSPO) are spreading.

Latest Trends

In 2024–2025, price volatility of palm oil, soybean oil, and sunflower oil increased due to climate variability (El Niño/La Niña) and changes in export policies of major producing countries, and Indonesia's palm oil export restrictions and expanded biodiesel blending mandates are directly affecting the international fats and oils market. The European Union has strengthened due diligence obligations for supply chains of raw materials such as palm oil and soybean oil through implementation of the EU Deforestation Regulation (EUDR).

In the energy sector, as demand for sustainable aviation fuel (SAF) surges, competition to secure used cooking oil (UCO) and animal fat feedstocks has intensified, and investment in HVO production facilities continues. In the food sector, alternative fats and oils made through precision fermentation and cell culture (structured lipids, microbial-derived oils) have entered the commercialization stage, and eco-friendly extraction technologies such as supercritical carbon dioxide extraction and enforcement of olive oil origin and grade labeling are also being strengthened.

Oil