Chapter 12 - Olive Oil Authenticity Evaluation by Chemical and Biological Methodologies

Abstract

Olive oil authenticity continues to be the target of many studies, reflecting its high economic value, not only for the producers in Mediterranean countries, but also for consumers worldwide. A vast amount of legislation relating to the accurate characterization and classification of olive oil has boosted scientific work on this subject. The main aim of these studies is to control changes of olive oil composition in order to protect both the consumer from adulteration and the industry from unfair competition, as well as preserving the prestigious image of olive oil itself. High-quality olive oils such as those labeled as Protected Designation of Origin (PDO) or mono-varietal olive oils can provide opportunities for very sophisticated types of adulterations that are very difficult to detect. Numerous attempts have been made to find suitable methods to authenticate the composition of olive oils. Generally, the analytical techniques used investigate one or more of the constituents of olive oil, such as triacylglycerols, fatty acids, sterols, alkanes, waxes and aliphatic alcohols. These can prove the presence/absence of adulterants, or verify geographical or cultivar origin by comparing with known samples or legally established limits. In recent years several reviews have been published using general techniques to authenticate olive oils or utilizing special techniques such as chromatographic techniques. Rather than being an exhaustive revision of published works, this chapter aims to summarize the analytical methods utilized so far to authenticate and provide quality control for olive oils, especially those categorized as extra virgin olive oil and virgin olive oil. Methods referred to are further divided into the type of technique used in the analytical methodology as follows: (i) chromatographic, (ii) spectroscopic/spectrometric and (iii) DNA-based techniques.