Theoretical note on difference tests used in sensory analysis

Abstract

The use of methods to evaluate differences or liking is very widespread for a variety of apparently simple sensory evaluation tests, either trained judges or consumers are being used. However, the most current tendencies in this area should be considered. That is why this article shows an introduction to the Thurstonian model, as well as its application on sensorial tests. The discussed theoretical treatment explains the detected differences in the execution of diverse protocols which include the test of differences, where a small change in the instructions given to the judges, could alter the proportion of right answers. A comment is made about the use of the binominal statistics for the analysis of tests difference, its limitations and the effect of adopted cognitive strategy by the consumers during the test. The Thurstonian model in the judges’ answers and the Signal Detection Theory are also analyzed. Moreover, some aspects related to Sequential Sensitivity Analysis, developed as a critical evolution of the Thurstonian model, are also covered.