Rapid and innovative instrumental approaches for quality and authenticity of olive oils
Authors: Valli Enrico , Bendini Alessandra , Berardinelli Annachiara , Ragni Luigi , Riccò Bruno , Grossi Marco , Gallina Toschi Tullia 
Published: October 2016

The quality of virgin olive oils is assessed through the determination of several analytical parameters, whose values must be within the ranges established by the different institutions involved. In addition to official methods, there is a strong need for simple, rapid, and environmentally friendly techniques for the quality control of virgin olive oils and for addressing the challenging task of determining geographical origin and detecting adulterants. Toward this purpose, some of the most interesting applications based on optical spectroscopic techniques, on the measurement of electrical characteristics and on the use of instruments equipped with electronic chemical sensors, including also other promising techniques are herein discussed. These techniques, adequately coupled with an appropriate statistical approach, appear to be promising for assessment of several quality‐related parameters. The prediction of sensory attributes and of the oxidative status of virgin olive oils have also been reviewed by adopting these selected techniques, which are also considered to be potentially appropriate solutions for identification of the geographical origin of virgin olive oils and to assess their adulteration with cheaper oils. Overall, the techniques discussed are promising and cutting‐edge approaches for the establishment of useful portable instruments for in situ monitoring of the quality of virgin olive oils.

Practical applications: The simple, rapid, and environmentally friendly analytical approaches discussed herein represent promising analytical tools for assuring the authenticity and monitoring the quality of virgin olive oils. Such innovative techniques and tools need to be ring‐tested and validated. Some innovative reviewed approaches will permit to develop useful portable instruments able to perform in situ appropriate controls also by small laboratories or olive oil mills with limited technical facilities. These equipments will be potentially usable also by trained “non‐professional analytical skilled” people. Some other approaches, rapid but more expensive, will be applicable mainly by quality control labs and will increase the number of samples analyzed per day, thus fostering laboratory proficiency and an effective fighting against olive oil fraud.

Quality analysis of virgin olive oil can be achieved by a set of chemical and sensory determinations. Reference chemical analyses are usually carried out in a laboratory by trained personnel and requires high costs and lengthy times to obtain results. Innovative techniques characterized by high accuracy, short response time, and possibility of in situ analysis to evaluate olive oil quality are reviewed herein. Such techniques can be divided in different groups depending on the principle of the methodology: 1) optical techniques, such as UV‐Vis, NIR, MIR, Raman, and fluorescence spectroscopy; 2) electrical techniques, such as electrical impedance spectroscopy, amperometry, and time domain reflectometry; and 3) electronic noses, electronic tongues and other promising approaches, where an array of electrodes or other technical solutions (PTR‐MS, FGC E‐nose, NMR) are used in conjunction with multivariate data analysis to obtain a chemical fingerprint of the product.