Effects of order of tasting in sensory difference tests using apple juice stimuli: development of a new model.

3-AFC discrimination tests between 2 confusable versions of apple juice were performed using a variety of interstimulus rinsing regimes, to investigate the effects of order of tasting on difference test sensitivity. The results were compared to predictions from the sequential sensitivity analysis (SSA) model and the conditional stimulus (CS) model, which have been developed to account for differences in model systems. These models did not account for the data for this beverage system. A new model was developed. This took a Thurstonian/signal detection approach but included new elements. It considered the gradual build-up of adaptation effects that would be encountered as a judge proceeded through a 3-AFC test with a relatively strong flavored food system. It further considered cognitive contrast effects, which had not been considered in the prior models. The model was named the sequential perception analysis (SPA) model and it accounted for the data found with the apple juice stimuli. The predictions of the model were precise enough to account for differences between individual triads, which the former models had not been able to do.