Triangle Taste Test and Sensory Evaluation: A Novel Application for Determining Supplement-Placebo Match in a Clinical Trial

The aim of this taste test was to determine if participants could perceive the differences between a powdered inulin fibre supplement and a crystallized xylitol sweetener when mixed with a masking substance (i.e. orange juice) to be used in an upcoming randomized controlled trial. To assess any detectable taste differences, the triangle test for similarity was used. Respondents were blinded and randomly selected to receive either the inulin fibre or xylitol sweetener, however, the investigators were not blinded. For this project, 42 judges were gathered. Out of these judges, 18 correctly picked the odd sample and 24 could not distinguish between samples. Further test to examine the proportion of discriminators showed that 6 (14.2%) of the judges were considered as discriminators or judges who were able to detect a difference with the upper end of the confidence interval at 16%. These results showed that the number of people who could discriminate between the different samples remained small and within the accepted range. Practical Applications: While supplement and placebo used regularly used in many clinical trials, their match is seldom tested. In this study, the taste match between the inulin fibre and the most commonly used placebo in intervention studies using inulin was testing using a triangle taste test. The results showed that people could not discriminate between groups. This provides further support to the methodological rigor for clinical trials where the group allocation is based on the assumption of similarity and seldom tested. Guidelines for clinical trials should mandate group comparability as a necessary test prior to the start of the trial to avoid potential bias what will compromise the methodological integrity.