John C. Castura

Comparison of TCATA and TDS for dynamic sensory characterization of food products

Temporal Check-All-That-Apply (TCATA) has been recently introduced as a method for temporal sensory product characterization. Building on the standard Check-All-That-Apply (CATA) question format, assessors select all the terms they consider applicable for describing the sensations they perceive, and they do so at each moment of the evaluation process. This research further investigates the TCATA method, through its application to products of varying complexity (yogurt, salami, cheese, orange juice, French bread, and marinated mussels) using consumers and trained panellists as assessors. More importantly, to deliver new methodological insights we compare TCATA to Temporal Dominance of Sensations (TDS). This comparison will aid researchers to select the temporal method best suited to their needs. Across three countries, six studies were conducted. Within-subjects experimental designs were used in Studies 1-3 and involved trained panellists using both TCATA and TDS on the same set of products. In Studies 4-6, between-subjects experimental designs were used, and the assessors, who were consumers, evaluated samples using either TCATA or TDS. The results confirmed that TCATA is suitable for measuring the temporal sensory characteristics of products. By enabling identification of several sensory characteristics that are concurrently perceived in products, the results from this research also suggest that TCATA may provide a more detailed description of the dynamics of the sensory characteristics of products. The TDS concept of dominance appears to decrease detailed description and discrimination of attributes that are simultaneously perceived, particularly when dealing with multiple sensory modalities. The practical implications of these differences are discussed.

Temporal Check-All-That-Apply Characterization of Syrah Wine.

Temporal Check-All-That-Apply (TCATA) is a new dynamic sensory method for which analysis techniques are still being developed and optimized. In this study, TCATA methodology was applied for the evaluation of wine finish by trained panelists (n = 13) on Syrah wines with different ethanol concentrations (10.5% v/v and 15.5% v/v). Raw data were time standardized to create a percentage of finish duration, subsequently segmented into thirds (beginning, middle, and end) to capture panel perception. Results indicated the finish of the high ethanol treatments lasted longer (approximately 12 s longer) than the low ethanol treatment (P ≤ 0.05). Within each finish segment, Cochrans Q was conducted on each attribute and differences were detected amongst treatments (P ≤ 0.05). Pairwise tests showed the high ethanol treatments were more described by astringency, heat/ethanol burn, bitterness, dark fruit, and spices, whereas the low ethanol treatment was more characterized by sourness, red fruit, and green flavors (P ≤ 0.05). This study demonstrated techniques for dealing with the data generated by TCATA. Furthermore, this study further characterized the influence of ethanol on wine finish, and by extension wine quality, with implications to winemakers responsible for wine processing decisions involving alcohol management.

Dynamic profiling of different ready-to-drink fermented dairy products: A comparative study using Temporal Check-All-That-Apply (TCATA), Temporal Dominance of Sensations (TDS) and Progressive Profile (PP)

Despite the several differences in ingredients, processes and nutritional values, dairy foods as yogurts, fermented milks and milk beverages are widely accepted worldwide, and although they have their sensory profiling normally covered by descriptive analyses, the temporal perception involved during the consumption are rarely considered. In this sense, the present work aimed to assess the dynamic sensory profile of three categories of fermented dairy products using different temporal methodologies: Temporal Dominance of Sensations (TDS), Progressive Profiling (PP), Temporal CATA (TCATA), and compare the results obtained. The findings showed that the different sensory characteristics among the products are basically related to their commercial identity. Regarding the methods, all of them collected the variations between samples with great correlation between data. In addition, to detect differences in intensities, TCATA showed to be the most sensitive method in detecting textural changes. When using PP, a balanced experimental design considering the number of attributes, time intervals, and food matrix must be weighed. The findings are of interest to guide sensory and consumer practitioners involved in the dairy production to formulate/reformulate their products and help them choosing the most suitable dynamic method to temporally evaluate them.

Comparison of static and dynamic sensory product characterizations based on check-all-that-apply questions with consumers

The aim of the present work was to compare static and dynamic sensory product characterizations based on check-all-that-apply (CATA) questions with consumers. Three studies involving a total of 310 consumers were carried out. In each study, a between-subjects experimental design was used to compare static sensory characterizations obtained using CATA questions with dynamic characterizations over a relatively short time period using temporal CATA (TCATA). Three different product categories were evaluated (orange juice, strawberry yogurt, and vanilla milk desserts) using 6-11 sensory terms. TCATA data were analysed as CATA considering fixed time periods throughout the evaluation. CATA and TCATA were compared in terms of frequency of use of the terms, sample discrimination, and sample and term configurations. Asking consumers to continuously select the attributes that applied to describe a product and to deselect those that no longer applied during the evaluation period did not substantially modify the average citation proportion of terms or the maximum citation proportion for individual terms for liquid and semi-solid products with a relatively fast oral preparatory phase. Although both methodologies provided similar information, additional insights on how similarities and differences among samples evolved during consumption were obtained with TCATA in the case of products that experience large temporal changes or attributes with strong time-dependency. CATA provided similar information as TCATA for sensory attributes that did not change substantially during the evaluation period. Results from the present work suggest that static and dynamic product sensory characterizations using CATA questions with consumers provide complementary information about consumer experiences with food products.

Chapter 2 – Statistics for Use in Discrimination Testing

Abstract This chapter considers statistics used in sensory difference testing from the perspective of business objectives and risks. Selection of an appropriate test method and experimental design must be aligned such that data analysis is able to provide meaningful information that relates back to the business objective and, where applicable, provides an actionable result. Various test methods are discussed and classified. Consideration is given to implications of analysis for unreplicated and replicated data, to statistical power, and to statistical tests for difference and equivalence. The link between experimental design and statistical analysis is stressed.