Temporal Rate-All-That-Apply (TRATA): A novel temporal method for sensory evaluation
This study introduces temporal rate-all-that-apply (TRATA) as a new temporal sensory method. It was inspired by rate-all-that-apply (RATA) and temporal check-all-that-apply (TCATA), but is most similar to multiple-attribute time intensity (MATI) in that the TRATA method allows for simultaneous rating of attribute intensities over time. Only attributes that are perceived are scaled. In this case study, the TRATA method was used to study the interaction between three sulphur compounds in model wine. These interactions have proven problematic when evaluated by sensory descriptive analysis (DA) due to the rapid changes in the headspace aromas and their intensities. TRATA provided insights into the dynamic sensory space of closely related samples whereas DA did not discriminate between samples.
The panel was trained to identify and scale the intensities of 10 sensory attributes and to do the TRATA task. A TRATA fading variant was used; whenever the intensity of an attribute was given, the response was initially opaque, but increased in transparency with time until it disappeared, indicating the absence of the sensation. This fading and disappearance visually reminded assessors to update their perceptions continuously. In some cases, fading created gaps in the data that were imputed using intensity data given before and after the gap. The panel evaluated three compounds at two levels in a full-factorial experiment in triplicate.
Results allowed us to investigate how the wine headspaces changed throughout the evaluation period. The temporal evolution was investigated using attribute intensity curves, which were then summarized using principal component analysis (PCA). Visualising the raw TRATA data allowed for the determination of how long sensory changes were perceived by each assessor. Raw curves were also compared to determine agreement of each assessor with the rest of the panel.
Vannevel, S., Brand, J., Castura, J.C., Buica, A., du Toit, W. (2021). Temporal Rate-All-That-Apply (TRATA): A novel temporal method for sensory evaluation. 14th Pangborn Sensory Science Symposium, 9-12 August. Online. (Poster).