Misdescription of edible oils: Flowcharts of analytical choices in a forensic view

The first commercial differentiation of edible oils, from a technological point of view, distinguishes them as non‐refined (e.g., virgin) and refined, due to the higher commercial value of the former. From this basic quality originates one of the most diffused oils' fraud, the misdeclaration of one or all the phases of the refining process (i). However there are many other ways in which an oil can be misdescribed, such as by: (ii) substituting all or a part of it with a similar but cheaper oil and (iii) declaring a false geographical or botanical origin. The present review addresses the problem of authenticity and misdescriptions of the oils (i–iii) through analytical schemes that can be followed and then used in a forensic view, to provide clues or evidence of fraud. It mentions official methods, known and innovative approaches, from chromatographic or derived methods to spectrometric, spectroscopic, DNA‐based, thermogravimetric, and calorimetric procedures for discriminating genuine from defrauded olive and seed oils. Practical applications: The forensic use of a chemical marker of a fraud, or of an analytical method is questionable if a legal limit or range is not yet defined, or when an official procedure has not been published at least in one State. On the other hand, a validated procedure or evidence can be used for legal purposes when it is possible to demonstrate that the scientific knowledge is more advanced than the existing official methods. In this paper known or promising methods, to discover and prove the most common misdescription of edible oils, which could be useful for a forensic application, are reported and reviewed.