Evaluating uncertainty in sensory analysis. A case study of the panel of tasters of the Dão Regional Wine Commission

Manuel Maria Pinto

doi:10.1051/ctv/ctv2021360122

Abstract

Metrological reliability in the sensory evaluation of products is of fundamental importance in ensuring the comparability of results. The issue of uncertainties regarding measured data in such contexts has led to new scientific approaches in the field of sensory analysis, which have become fundamental to studies that seek to compare results of sensory measurement and analysis, including studies regarding wine. The new normative framework, ISO/IEC 17025:2017, which replaces the previous version ISO/IEC 17025, published in 2005, draws attention to the concept of measurement uncertainty, stating that it should be considered by laboratories when assessing conformity and quantifying risks arising in decision-making processes. The present work examines the evaluation of uncertainty and its importance for the interpretation of results from sensory analyses, examining sensory analysis tests related to the certification of the Designation of Origin “Dão”, the Designation of Origin “Lafões” and the Geographical Indication “Terras do Dão”, carried out by a panel composed of 20 tasters of the Dão Regional Wine Commission, trained and accredited by the standard NP ISO/IEC 17025:2018. The results achieved led to a conclusion that the panel presented different values of uncertainty regarding the tests to determine sensory attributes. The results and respective values of uncertainty made it possible to assess the performance of the panel of tasters and to establish a level of risk (false accept, false reject and statistical assumptions) for decision rules used when issuing statements of conformity. In this study, a new methodology was presented to determine an estimate of uncertainty to be applied in the interpretation of results related to sensory analysis tests of wines for the certification of Designation of Controlled Origin “Dão”, Designation of Origin “Lafões” and Geographical Indication “Terras do Dão. This progress led to an evolution in the day-to-day work of the Dão Regional Wine Commission tasting chamber enabling greater solidity in the opinions issued, in line with the requirements of the reference standard NP ISO/IEC 17025: 2018.

Highlights

In recent times scientists have succeeded in developing sensory testing as a formalized, structured, and codified methodology, trying to develop new sensory methods and refining the existing ones (Meilgaard et al, 2016)
As stated by the Nordic Committee on Food Analysis (2013), the importance of measurement uncertainty has gained increased acceptance within most fields of metrology, and there is a vast amount of literature on the subject within other areas, outside the scope of the sensory analysis
The trends in the evolution of sensory evaluation applied to quality control in the last 20 years have been notorious with the focus on three main areas: (i) on the establishment of a standard programme of sensory evaluation and in-house training, together with the instrumental analyses, aimed at assuring product quality; (ii) on food quality certification, requiring a method of panel performance evaluation; (iii) on parameters which could contribute to differentiate products according to the quality grade as well as on the modelization of quality standards (Nguyen et al, 2014)

Summary

Introduction

In recent times scientists have succeeded in developing sensory testing as a formalized, structured, and codified methodology, trying to develop new sensory methods and refining the existing ones (Meilgaard et al, 2016). As stated by the Nordic Committee on Food Analysis (2013), the importance of measurement uncertainty has gained increased acceptance within most fields of metrology, and there is a vast amount of literature on the subject within other areas, outside the scope of the sensory analysis. In this specific field, the literature is scarce, becoming a rarely touched subject among sensory scientists. Given the inherent subjectivity and variability of human evaluators and to make measurements of food analysis more objective, trained panels were developed since the 1940’s and the field of sensory evaluation emerged and clearly progressed. The trends in the evolution of sensory evaluation applied to quality control in the last 20 years have been notorious with the focus on three main areas: (i) on the establishment of a standard programme of sensory evaluation and in-house training, together with the instrumental analyses, aimed at assuring product quality; (ii) on food quality certification, requiring a method of panel performance evaluation; (iii) on parameters which could contribute to differentiate products according to the quality grade as well as on the modelization of quality standards (Nguyen et al, 2014)

Methods

Results

Conclusion