What is the chemical composition of virgin olive oils?

Virgin olive oils have a peculiar chemical composition compared to other vegetable oils.

One of the reasons for its specific composition is that most of the vegetable oils are extracted from seeds using solvents, with what only the fat is removed; on the contrary, Olive oils can be extracted directly by mechanical means from the olives because the olive oil is located in the fleshy part. This makes that many of the compounds that are naturally associated to the fat in the olives pass into the virgin olive oil.

Another reason is that the olive contains “exclusive” components that any other vegetable oil contains, and that have a significant intervention for the health and for the organoleptic characteristics of the oil.

Finally, the profile of the fatty acids in olive oil, with a preponderance of the oleic acid, also makes it unique within the oils of vegetable origin.

In the composition of virgin olive oils are distinguished two main fractions with the following items:

A) Saponificable Fraction (98-99%)
   A.1 Triglycerides (96%)
   A.2 Diglycerides (2%)
   A.3 Free fatty acids (0.5%)

B) Unsaponificable fraction (1-2%)
   B.1. Compounds from fatty acids:
          B.1.1 Phospholipids (40 - 135 mg/kg)
          B.1.2 Waxes (250 mg/kg approx.)
          B.1.3 Esters of sterols.
   B.2. Non-fatty acids compounds:
          B.2.1 Hydrocarbons
                B.2.1.1 Squalene (8000 mg/kg)
                B.2.1.2 β-carotene, a precursor of vitamin A (4 mg / kg)
          B.2.2 Fatty alcohols (1500-2000 mg/kg)
          B.2.3 Sterols (1000-2000 mg/kg)
          B.2.4 Tocopherols, vitamin E (50 - 300 mg/kg)
          B.2.5 Pigments (40 mg/kg)
          B.2.6 Polyphenols (50 - 800 mg/kg)
          B.2.7 Volatile and aromatic

Comments about the Chemical composition of Extra Virgin Olive Oils

a)    Olive oil is mainly composed by the saponificable fraction, i.e. by fat. Most of this fat is composed of triglycerides like all vegetable oils, as it is the way that plants synthesize fats. Diglycerides and free fatty acids would be non finished parts, or are the result of the breakdown of triglycerides.

b)    Unsaponificable fraction in olive oils is very small compared to Saponificable. It contains a large number of components in small quantities. These compounds are responsible for some of the most important characteristics of the Virgin olive oil as the color, flavor and aroma; through antioxidant and anti-inflammatory properties beneficial to health.

c)    The quantities of each unsaponifiable fraction compounds can vary significantly, since they depend on many factors.

d)    Most of the unsaponifiable fraction is lost in the refining process.