Ilegal blends between olive and soft deodorized oils (2021)

Abstract

These data were generated in our lab, with the help of several laboratory assistants and master students, within the OLEUM project (http://www.oleumproject.eu): ‘Advanced solutions for assuring the authenticity and quality of olive oil at a global scale’ . The general objectives of the Project focus on olive oil fraud detection in a way that it improves the existing analytical methods and it has developed new strategies of analysis. It has been organized in seven work packages distributed in a number of tasks. This work is within Work Package 4 (‘Analytical solution addressing olive oil authentication issues’), and it concentrates on the detection of illegal blends, i.e. of illicit processing (deodorization) in extra virgin olive oil (EVOO)

In our endeavor to detect soft deodorized olive oil in EVOO we have focused on the convenience of using two new factors (R1 and R2) obtained as a result of combining the total DAG content and the free acidity value of the samples under the microscope. We chose this methodology following our trend of using well-known, widely reputable routine parameters, avoiding in this way more complicated strategies that, although commonly used in the field of olive oil authentication, could require a more specific personnel training and laboratory apparatus. According to this, we demonstrated that since there is a relationship between free acidity and DAG concentration (both of them come from triacylglyceride hydrolysis and/or biosynthesis), and that such relationship breaks once the oil has gone through a refining process (free fatty acids are removed during the deodorization stage), it was possible to detect the presence of soft deodorized oil in EVOO by using a mathematical combination of both measurements at least to a certain extent. We actually proposed two factors to confirm the absence of soft deodorized oils in EVOO: R1 (10 x free acidity/DAGexp) >/= 0.23 and R2 (DAGexp-DAGtheor) < 0, in genuine EVOO, and we established that such approach was useful to detect the presence of soft deodorized olive oil when this was at least at 30 % in the mixture (Food Chemistry, volume 330, 2020, 127226). Samples were provided by Fera (Fera Science Ltd, Sand Hutton, York) and Institut des Corps Gras (ITERG, Canéjan, France).