| Guide to Olive Oil Analysis | | |
Extra Virgin Olive Oil
Extra virgin olive oil is a product of great importance in our diet, which is why it is essential to ensure its quality.
The analyses performed depend on the intended use of the product—whether for personal use or for sale—as well as the product’s designation (e.g., PGI, PDO, or intended for export), the product’s age, and any suspicion of contamination or adulteration.
The analytical parameters of an oil can be divided into quality parameters and authenticity parameters. The analyses to be performed on an oil are specified in EEC Regulation 2568/91. |
Significance of the Parameters Analyzed in EV
Olive Oil The analyses performed by C.B.A. on extra virgin olive oil include various quality and authenticity parameters, such as acidity, peroxide value, the presence of polyphenols and tocopherols, ultraviolet spectrophotometric analysis, fatty acid composition, and sensory analysis. Acidity measures the amount of free fatty acids present in the oil; the peroxide value indicates the degree of oxidation and the quality of the oil; polyphenols and tocopherols are antioxidants naturally present in the oil, and their quantity is an indicator of quality. Ultraviolet spectrophotometric analysis measures the oil’s degree of oxidation and can reveal the presence of refined oil in virgin olive oil. Fatty acid composition can indicate the presence of seed oils. | | Analytical Parameters in Detail
: Acidity
This quality parameter expresses the percentage of free fatty acids in the oil. These are formed as a result of reactions that occur inside the olives.
The acidity of an oil is expressed as grams of oleic acid per 100 grams of oil. Analytically, it is determined by titration with an alkali (usually KOH) in the presence of phenolphthalein.
Acidity increases due to:
- insect damage to the olives -
damage during harvesting and transport of the olives -
prolonged storage of the olives before pressing -
fermentation of the olives during storage -
the technology used during pressing
Peroxide Value This value measures the degree of oxidation in an oil: in fact, peroxides form in the oil as a result of the action of oxygen.
This parameter therefore indicates the oil’s state of preservation: the lower the value, the better the oil’s quality.
Polyphenols
Polyphenols are antioxidants naturally present in extra virgin olive oil, and their quantity serves as an indicator of the product’s quality. PDO and PGI regulations often set a minimum quantity.
Tocopherols
Tocopherols are naturally present in extra virgin olive oil, and vitamin E is one of them; here too, the amount present is an indicator of the oil’s quality. PDO and PGI regulations often set a minimum quantity.
Ultraviolet (UV) Spectrophotometric Analysis Like the peroxide value, this measure assesses the oil’s oxidation status and, therefore, its state of preservation. It also helps detect the presence of refined oil in virgin olive oil.
It is based on the observation of UV light absorption at wavelengths of 232, 262, 268, and 274 nm, at which the conjugated dienes and trienes formed during refining processes absorb light. Values exceeding the K268 and Delta K limits for an extra virgin olive oil may indicate contamination by olive-pomace oils and refined olive oils. It is therefore a very important parameter for assessing both the quality and authenticity of an oil.
Fatty Acid Methyl Esters (or Acid Composition)
The fatty acid composition is characteristic of each type of fruit or seed from which the oil is derived; therefore, an abnormal composition in olive oils may indicate the presence of seed oils. PGI and PDO regulations often set limits for their composition.
Olive oil has a characteristic fatty acid composition, the analysis of which can reveal the presence of oils of different origins or those obtained through industrial processes.
In olive oils—both virgin and pomace—triglycerides are found that contain almost exclusively unsaturated fatty acids in position 2. Saturated fatty acids, if present, never exceed 2%.
In oils obtained through chemical synthesis, esterification occurs randomly, and it is common to find saturated fatty acids in position 2; their presence allows for the detection of the addition of esterified oils to olive oils.
Through this gas chromatographic analysis, it is therefore possible to determine the authenticity of an oil.
Analysis of the Unsaponifiable Fraction The following components are determined in the unsaponifiable fraction: the sterol component, the content of polyterpene alcohols (erythrodiol and uvaol), and the content of higher aliphatic alcohols and stigmastadienes.
Gas Chromatographic Analysis of Sterols
The sterol fraction depends on the fruit or seed from which the oil is obtained. Its composition—both qualitative and quantitative—is not influenced by any genetic modifications made to the plant, unlike the fatty acid content.
Stigmastadienes
Stigmastadienes are formed during certain stages of the oil refining process. This analysis is useful for assessing the addition of refined oils to virgin olive oils. | | Seed Oils and Other Oils
Our laboratory also performs analyses on seed oils (sunflower, corn, peanut, etc.) as well as other vegetable oils in general, for food, animal feed, or other uses.
If you have any questions or requests, please feel free to contact us with no obligation. | |
Which Analyses to Perform
The PDF attached below provides examples of combinations of analyses that can be performed. In reality, there are many types of analyses typically performed on oil, and they depend on the specific issues presented by the product. | | 
Guide to Analyses of Extra Virgin Olive Oil | | | |  |  |  | | |
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