How to discover soft deodorised olive oil?
To blend deodorised olive oil in virgin olive oil is a fraud for global standards and rules but it's difficult to find it. Reseachers partecipate do a workshop in Madrid to discuss the problem
For the detection of soft deodorised olive oil blended into edible virgin olive, participants to Workshop on olive oil authentication in Madrid clearly mentioned that the major difficulty to tackle this issue concerns the poor knowledge regarding the deodorisation processes used by industries and to get access to representative samples of soft deodorised olive oil.
Such information is a prerequisite that will help to identify potential markers, to develop appropriate analytical methods, and to estimate limits of detection and quantitation.
In addition to what was mentioned during the presentations of the first day, additional analytes that could be used for the detection of soft deodorisation of olive oil are: carotenes, polar compounds, steryl glucosides, steradienes, and in a broader sense chemical profiling (including volatile profiles) and sensory parameters.
For that purpose, common analytical methods in use are sensory panel testing, chromatography (liquid or gas) and spectrometry (fluorometry, NIR spectroscopy, nuclear magnetic resonance -
NMR, mass spectrometry).
In addition to technical limitations with specific analytical methods - such as a lengthy procedure
for the determination of DAGs, the cost of solvents, or the influence of storage condition on the level of PPPs - the main limitation is the fact that certain methods used for the detection of soft deodorised oil are not fully validated.
Drawbacks with the specificity of methods (e.g. interferences of methanol liberated by the action of pectinase during the malaxation of olives), the sensitivity (e.g. Stigmastadiene could not be detected in oils deodorised at low temperatures, or low levels of degradation products in edible virgin olive oils blended with low levels of soft deodorised oil), and the calibration (e.g. NIR) of methods were mentioned. The number of available Certified Reference Materials (CRMs) (e.g. for training sensory panels) and the need to perform systematically ring tests to assess the performance of the most relevant methods were also highlighted.
As a result, participants suggested evaluating the following strategy for detecting adulteration
with soft deodorised oils:
- to collect reliable information on the soft deodorisation process(es),
- to consider creating a facility to produce soft deodorised olive oil under conditions that are
close to industrial refining, and
- to study in a systematic way the changes in oil composition due to soft deodorisation.