Olive oil

Food, Plant source foods, Vegetable oils and derivatives

Consumption area(s) (countries that consumed more than 1.5 kg per person annually in 2022): Albania 🇦🇱, Algeria 🇩🇿, Andorra 🇦🇩, Australia 🇦🇺, Canada 🇨🇦, Cape Verde 🇨🇻, Croatia 🇭🇷, Cyprus 🇨🇾, France 🇫🇷, Greece 🇬🇷, Iceland 🇮🇸, Israel 🇮🇱, Italy 🇮🇹, Jordan 🇯🇴, Lebanon 🇱🇧, Libya 🇱🇾, Liechtenstein 🇱🇮, Monaco 🇲🇨, Morocco 🇲🇦, New Zealand 🇳🇿, Oman 🇴🇲, Portugal 🇵🇹, San Marino 🇸🇲, Spain 🇪🇸, Switzerland 🇨🇭, Syria 🇸🇾, Tunisia 🇹🇳, Turkey 🇹🇷, Vatican City 🇻🇦

Chemical composition:

• Saponifiable fraction: ~99%
  • Saturated fatty acids: 14.5%, including 13% palmitic acid and 1.5% stearic acid
  • Unsaturated fatty acids: >85%, including 70% oleic acid and 15% linoleic acid
• Unsaponifiable fraction: ~1%
  • Carotenoids, chlorophyll, sterols, tocopherols

Chemical/physical properties:

• Smoke point: variable depending on oil quality
• Boiling point: 299 °C
• Density: 916 g/L

Introduction

Olive oil is a liquid fat obtained by pressing whole olives, the fruit of Olea europaea, a traditional tree crop of the Mediterranean Basin. Its production involves pressing or oil extraction methods, each of which can significantly influence the final quality of the product.

Description of olive oil

Olive oil is widely used in cooking, both for frying and as a dressing for salads and various dishes. Beyond culinary use, it is also employed in cosmetics, pharmaceuticals, soaps, and as fuel for traditional oil lamps. It holds symbolic and ritual value in several religions. The olive tree is one of the three main food plants of the Mediterranean diet, alongside wheat and grape, and its cultivation in the Mediterranean dates back at least to the 8th millennium BCE.

Global olive oil production is dominated by a few Mediterranean countries. In 2022, Spain was the leading producer, accounting for 24% of the world total, followed by Italy, Greece, and Turkey. The quality and composition of olive oil vary according to the cultivar, altitude, harvest timing, and extraction process. After pressing, the remaining solid residue known as pomace still contains a small amount of oil (about 5–10%), which can only be recovered using chemical solvents in specialized facilities, producing pomace oil.

Extra virgin olive oil (EVOO) is considered the most valuable grade and must not exceed 0.8% acidity, a parameter indicating the presence of free oleic acid, which influences flavor and shelf life. This acidity is unrelated to pH; it refers instead to the amount of free fatty acids released from the breakdown of triglycerides, which increases hydrolytic rancidity and compromises the organoleptic and nutritional qualities of the oil.

History of olive oil

Olive oil has been a cornerstone ingredient of Mediterranean cuisine since antiquity, holding a central role in Greek and Roman civilizations. Wild olives, native to Asia Minor, were already being harvested in the 8th millennium BCE. Beyond its culinary use, olive oil served in religious rituals, medicinal ointments, as fuel for lamps, and for skin care. In Greece, athletes would rub it over their bodies before training. It was even regarded as a contraceptive, with Aristotle describing a mixture of olive oil, cedar oil, and other ingredients to prevent pregnancy.

The origin of olive cultivation remains uncertain, but some studies suggest it may have first developed in Persia and Mesopotamia, later spreading to the Levant, North Africa, and Egypt. The olive tree reached Greece, Carthage, and Libya in the 8th century BCE, brought by the Phoenicians. In Crete, it was present as early as 2500 BCE. During the Minoan and later Mycenaean periods, olive oil became a key element of the Mediterranean economy. With the expansion of Greek colonies, olive cultivation reached Spain and spread further under the Roman Empire. In the 16th century, it was introduced to the Americas, particularly in Chile, Argentina, and California.

The earliest archaeological evidence of olive oil production dates to 6000 BCE in Galilee, with further proof from 4500 BCE in Haifa. In Ebla, documents from 2400 BCE mention royal olive groves. Dynastic Egyptians, before 2000 BCE, imported olive oil from Crete, Syria, and Canaan. On Naxos, traces of olive oil have been found in jars over 4,000 years old. In Minoan civilization, olive oil was a symbol of wealth and held a role in religious ceremonies. In later centuries, the Mycenaeans made it one of their main exports.

Under the Roman Empire, the production and trade of olive oil expanded dramatically. According to Pliny the Elder, olive oil produced in Italy in the 1st century CE was of high quality and affordably priced. The Romans developed new extraction techniques, such as the trapetum, and promoted cultivation throughout the Mediterranean Basin. Some Roman olive mills are still visible today and, in certain regions, have been in use for centuries. Over time, olive oil processing was further refined with innovations such as hydraulic pressing, improving the productivity of this essential commodity.

Olive oil production method

The extraction of olive oil is carried out primarily through mechanical processes, which distinguish virgin oils from those produced using physical and chemical methods—such as seed oils, refined olive oils, and pomace oils. The two most common techniques are pressing and centrifugation. Oils that undergo chemical treatments must be refined to become edible, but they cannot be classified as virgin. For this reason, the quality of olive oil largely depends on the extraction method used.

Mechanical production lines vary according to the methods applied in each stage of the process. Facilities differ in production capacity, level of mechanization, qualitative and quantitative yield, and production costs. A mill typically follows five main stages: preliminary operations, crushing (or milling), extraction of the olive must, separation of oil from water, and storage and bottling. Each step directly affects the final quality of the oil, making careful process control essential.

The crushing or milling of olives can be performed using various systems. Common options include millstones, hammer crushers, toothed-disc crushers, or blade crushers. The choice of method influences cell breakage and the oil yield. In the following stage, the oil is separated from water through different techniques, such as the pressing system, percolation (Sinolea), or centrifugal separation (decanter).

Technological advancements have improved the extraction process, enabling greater efficiency and increasingly higher quality. Centrifugation has largely replaced pressing, thanks to its ability to recover a greater quantity of oil with lower oxidative impact.

Classification of olive oil

Classification of olive oil is determined primarily by the extraction method, the acidity level, and the wax content, although regulations may vary from country to country. To keep things straightforward, the following refers to the European Union standard, which differs only slightly from most other international guidelines.

For edible oils, the hierarchy of quality is as follows:

• Extra virgin olive oil (EVOO) – obtained exclusively through mechanical processes, with a maximum acidity of 0.8% and wax content up to 250 mg/kg.
• Virgin olive oil – extracted by mechanical means, with a maximum acidity of 2.0% and wax content up to 250 mg/kg.
• Refined olive oil – produced by refining lampante oils using physical and chemical methods, with a maximum acidity of 0.3% and wax content up to 350 mg/kg.
• Olive oil blend – a mixture of refined olive oil and virgin olive oil, with a maximum acidity of 1.0% and wax content up to 350 mg/kg.
• Olive-pomace oil – made by combining refined pomace oil with virgin olive oil, with a maximum acidity of 1.0% and wax content above 350 mg/kg.

Nutritional facts table

Please note that nutritional values can vary slightly depending on olive type

Nutrients	Per 100 g
Calories (kcal)	899
Total fat (g)	99.9
———Saturated fat (g)	15.32
Cholesterol (mg)	0
Sodium (mg)	0
Total carbohydrates (g)	0
———Dietary fiber (g)	0
———Total sugar (g)	0
Protein (g)	0