Reference materials (RMs) for supporting sensory panel tests
The IOC Panel test is both a qualitative and quantitative method, since its application results in the classification of samples based on the median of the predominant defect and the presence or not of the fruity attribute. For its use, it is necessary that tasters must be correctly trained and supervised for correct classification of samples and for correct recognition of the intensities of perceived attributes.
In this context, OLEUM project is engaged in reinforcing the methodology for the sensory evaluation improving its reproducibility by the adoption of supporting tools (reproducible sensory reference materials) for training the panels and undergoing quality control of the panellists, through the design of a global procedure named Quantitative Panel Test.
The introduction of reference materials obtained by mixing pure molecules in specific concentrations, with an open source composition and thus reproducible, will allow to overcome some limits of those obtained from natural matrix and will offer several advantages including the preparation in each laboratory, the reproducibility over time, and/or the possibility of purchase, which would mean unlimited availability.
Two new artificial reference materials (for the aroma of winey-vinegary and rancid defects) have been formulated ad hoc to resembling these sensory defects using specific mixtures of volatile molecules in specific concentrations relevant for the sensory attribute to be created and based on their odorous threshold (selection of volatile compounds obtained after a deep study of sample profiles characterized by the presence of specific sensory descriptors).
A protocol for the reference materials practical application has been defined and shared with the six sensory panels involved in the project; it includes three different parts: the evaluation of their representativeness (with respect to real samples); the determination of panels’ detection threshold for each one and their shelf-life evaluation over time.
The stock solutions of each reference material and odourless refined olive oil needed for the detection threshold evaluation were shipped to sensory panels and all sensory results were collected for their processing.
The reference materials’ formulation and practical application will improve the proficiency of the sensory Panels and will contribute to the improvement of the IOC methodology specifically for the selection, training and monitoring of skilled virgin olive oil tasters.
Ramón Aparicio-Ruiz, Diego L. García González (CSIC) and Sara Barbieri (UNIBO)