Temporal dominance of sensations and sensory profiling: A comparative study

A Comparison of Temporal Dominance of Sensation (TDS) and Quantitative Descriptive Analysis (QDA™) to Identify Flavors in Strawberries

Temporal dominance of sensations (TDS) is a rapid descriptive method that offers a different magnitude of information to traditional descriptive analysis methodologies. This methodology considers the dynamic nature of eating, assessing sensory perception of foods as they change throughout the eating event. Limited research has applied the TDS methodology to strawberries and subsequently validated the results against Quantitative Descriptive Analysis (QDA™). The aim of this research is to compare the TDS methodology using an untrained consumer panel to the results obtained via QDA™ with a trained sensory panel. The trained panelists (n = 12, minimum 60 hr each panelist) were provided with six strawberry samples (three cultivars at two maturation levels) and applied QDA™ techniques to profile each strawberry sample. Untrained consumers (n = 103) were provided with six strawberry samples (three cultivars at two maturation levels) and required to use TDS methodology to assess the dominant sensations for each sample as they change over time. Results revealed moderately comparable product configurations produced via TDS in comparison to QDA™ (RV coefficient = 0.559), as well as similar application of the sweet attribute (correlation coefficient of 0.895 at first bite). The TDS methodology however was not in agreement with the QDA™ methodology regarding more complex flavor terms. These findings support the notion that the lack of training on the definition of terms, together with the limitations of the methodology to ignore all attributes other than those dominant, provide a different magnitude of information than the QDA™ methodology.

PRACTICAL APPLICATION

A comparison of TDS to traditional descriptive analysis indicate that TDS provides additional information to QDA™ regarding the lingering component of eating. The QDA™ results however provide more precise detail regarding singular attributes. Therefore, the TDS methodology has an application in industry when it is important to understand the lingering profile of products. However, this methodology should not be employed as a replacement to traditional descriptive analysis methods.

Can we monitor adaptation of juvenile goats to a new social environment through continuous qualitative behaviour assessment?

We aimed to verify whether Continuous Qualitative Behaviour Assessment (10 observers used a list of six qualitative descriptors) paired with Temporal Dominant Behavioural Expression (the same observers were asked to select the dominant descriptor and to score its intensity level) was able to monitor fluctuations of animal behaviour expression over time. We applied these techniques to three groups of juvenile goats either weaned (group C), or un-weaned (groups WOM and WM). Each animal was separated from its group, moved to group C and tested for 30 min either while their mothers were at pasture, or while their mothers were in an adjacent pen (group WOM and WM, respectively). Animals from group C were separated from their group and immediately reintroduced to it. TDBE duration and score of each descriptor of behavioural expression were able to detect differences among groups but were unable to describe how the behaviour of the goats changed as the time progressed. TDBE curves described the evolution of each behavioural expression of each animal over time but were unable to detect differences among groups. The χ2 test conducted on peaks of dominance, albeit displaying the variations of the behavioural expression over time and allowing the assessment of differences among groups, focussed on occurrences of higher agreement between observers while neglecting most of the information concerning the descriptors above the level of significance. Conversely, based on mixed analysis of variance with the fixed effects of group, test interval and group x test interval (animal nested into group and observer were considered to be random), most of the descriptors were able to discriminate the three experimental groups while preserving the information on the fluctuations of the behavioural expression of the animals during the test.

Temporal Texture Profile and Identification of Glass Transition Temperature as an Instrumental Predictor of Stickiness in a Caramel System

Stickiness is an important texture attribute in many food systems, but its meaning can vary by person, product, and throughout mastication. This variability and complexity makes it difficult to devise analytical tests that accurately and consistently predict sensory stickiness. Glass transition temperature (T_g ) is a promising candidate for texture prediction. Our objective is to elucidate the temporal profile of stickiness in order to probe the relationship between T_g and dynamic stickiness perception. Nine caramel samples with diverse texture and thermal profiles were produced for sensory testing and differential scanning calorimetry. Sixteen trained panelists generated stickiness-relevant terms to be used in a subsequent temporal dominance of sensation (TDS) test with the same panelists. Following the TDS study, these panelists also rated samples for overall tactile and oral stickiness. Stickiness ratings were then correlated to TDS dominance parameters across the full evaluation period and within the first, middle, and final thirds of the evaluation period. Samples with temporal texture profiles dominated by tacky, stringy, and enveloping attributes consistently received the highest stickiness scores, although the correlation strength varied by time period. T_g was found to correlate well with trained panelist and consumer ratings of oral (R²_trained = 0.85; R²_consumer = 0.96) and tactile (R²_trained = 0.78; R²_consumer = 0.79) stickiness intensity, and stickiness intensity ratings decreased with T_g of completely amorphous samples. Further, glassy samples followed a different texture trajectory (brittle-cohesive-toothpacking) than rubbery samples (deformable-tacky-enveloping). These results illuminate the dynamic perception of stickiness and support the potential of T_g to predict both stickiness intensity and texture trajectory in caramel systems.

Bolus matters: the influence of food oral breakdown on dynamic texture perception

This review article focuses on design of food structure, characterisation of oral processing by boli characterisation and dynamic texture perception. Knowledge of the food properties governing bolus formation and bolus properties determining temporal changes in texture perception is of major importance. Such knowledge allows academia to better understand the mechanisms underlying texture perception and food industry to improve product texture. For instance, such knowledge can be used for developing foods with desired texture perception that fit in a healthy diet or that are customized to specific consumer groups. The end point of oral processing is the formation of a safe-to-swallow bolus. The transitions of solid and soft solid foods into bolus are accompanied by tremendous modifications of food properties. The review discusses dynamic changes in bolus properties resulting in dynamic changes of texture perception during oral processing. Studies monitoring chewing behaviour are discussed to complement the relationships between bolus properties and dynamic texture perception. We conclude that texture perception evolves over mastication time and depends on food properties, such as mechanical properties, mainly in the beginning of oral processing. Towards the middle and end of oral processing, bolus properties depend on food properties and explain texture perception better than food properties.

Dynamic sensory description of Rioja Alavesa red wines made by different winemaking practices by using Temporal Dominance of Sensations

BACKGROUND

Although sensory description of wines in scientific literature is very large, there is an evident lack of studies describing wines from a dynamic approach. The objective of this study was to describe the evolution of the sensations perceived in red wines from Rioja Alavesa by using Temporal Dominance of Sensations (TDS) and also to compare wines made with the two winemaking procedures used in Rioja Alavesa: carbonic maceration (CM) and destemming (DS).

RESULTS

Ten sensory attributes were evaluated in eight wines (four CM and four DS wines) in triplicate by a panel of 16 trained assessors. Red/black berry and woody aromas were dominant firstly, whereas heat, astringent, bitter and pungent sensations were dominant later. CM wines showed higher dominance for woody, spicy, pungent and acid sensations and lower dominance for red/black berry aroma and astringency than DS wines.

CONCLUSION

This study is the first to describe Rioja wines from a dynamic approach and it also provides information about the dynamic sensory differences between wines made by CM or by DS. In this sense, this work shows the usefulness of TDS to describe and differentiate wines and to provide additional information to the conventional static descriptive analysis. © 2015 Society of Chemical Industry.

Effect of preservative addition on sensory and dynamic profile of Lucanian dry-sausages as assessed by quantitative descriptive analysis and temporal dominance of sensations

The quantitative descriptive analysis (QDA) was combined with temporal dominance of sensations (TDS) to assess the sensory properties of Lucanian dry-sausages either added with nitrate, nitrite and l-ascorbic acid (NS), or not (NNS). Both QDA and TDS differentiated the two groups of sausages. NNS products were perceived with higher intensity of hardness (P<0.05) and tended to be perceived with higher intensities of flavor (P<0.10), pepper (P<0.20), and oiliness (P<0.20), while resulting lower in chewiness (P<0.20). TDS showed that in all the sausages hardness was the first dominant attribute; then, in NNS products flavor remained dominant until the end of tasting, whereas in NS products oiliness prevailed. In conclusion, TDS showed that the perception of some textural parameters, such as oiliness, during mastication was more dominant in NS products, whereas using conventional QDA this attribute appeared higher in sausages manufactured without preservatives. Therefore, TDS provided additional information for the description and differentiation of Lucanian sausages.

Respective impact of bread structure and oral processing on dynamic texture perceptions through statistical multiblock analysis

Texture perception is a multidimensional and dynamic phenomenon resulting from both the initial structure of food and its breakdown during oral processing. The aim of this study is to identify the respective contribution of food and bolus properties to temporal changes in texture perceptions during bread consumption. For this purpose, the perception dynamics of three French baguettes with dif\ferent structures were assessed through Temporal Dominance of Sensations and Progressive Profiling. Samples of crumb with and without crust were tasted by trained panelists. The intensities of nine texture attributes were evaluated at three key stages of oral processing (10%, 40% and 100% of individual swallowing time) using the Progressive Profiling method. Six of them were related with a Multiblock Partial Least Squares (MB-PLS) regression to the initial bread properties and to some bolus properties measured at these three stages. The evolution during oral processing of some attributes such as "soft", "dry", "doughy" and "sticky" was more influenced by modifications of bolus properties than by the initial characteristics of the breads. Among bolus properties, the MB-PLS highlighted that the hydration and texture properties of the bolus had a greater impact on texture perceptions than bolus structure. The "aerated" perception was more affected by the crumb structure, while the "heterogeneousness" and the "crispiness" were more affected by the presence of crust. This study thus contributes to improving our understanding of dynamic texture perceptions through a statistical model that takes the physical properties of bread and bolus during oral processing into account.

Development of a Time-Intensity Evaluation System for Consumers: Measuring Bitterness and Retronasal Aroma of Coffee Beverages in 106 Untrained Panelists

In order to develop products that are acceptable to consumers, it is necessary to incorporate consumers' intentions into products' characteristics. Therefore, investigation of consumers' perceptions of the taste or smell of common beverages provides information that should be useful in predicting market responses. In this study, we sought to develop a time-intensity evaluation system for consumer panels. Using our system, we performed time-intensity evaluation of flavor attributes (bitterness and retronasal aroma) that consumers perceived after swallowing a coffee beverage. Additionally, we developed quantitative evaluation methods for determining whether consumer panelists can properly perform time-intensity evaluation. In every trial, we fitted an exponential function to measured intensity data for bitterness and retronasal aroma. The correlation coefficients between measured time-intensity data and the fitted exponential curves were greater than 0.8 in about 90% of trials, indicating that we had successfully developed a time-intensity system for use with consumer panelists, even after just a single training trial using a nontrained consumer. We classified participants into two groups based on their consumption of canned coffee beverages. Significant difference was observed in only AUC of sensory modality (bitterness compared with retronasal aroma) among conventional TI parameters using two-way ANOVA. However, three-way ANOVA including a time course revealed significant difference between bitterness and retronasal aroma in the high-consumption group. Moreover, the high-consumption group more easily discriminated between bitterness and retronasal aroma than the low-consumption group. This finding implied that manufacturers should select consumer panelists who are suitable for their concepts of new products.