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

Abstract

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.

Effect of a warm‐up sample on stabilizing the performance of untrained panelists in time–intensity evaluation

“…In ordinary studies, trained panelists performed the evaluation (ASTM International, ; Dehlholm, ; Kunieda, ), because researchers speculated that it might be difficult for untrained panelists to perform time–intensity evaluation. Based on this situation, Gotow et al () developed a time–intensity evaluation system for use with untrained panelists. The typical time–intensity evaluation systems adopt a lever, rotating knob, joystick, or computer mouse as a response device.…”

“…Movement of the response device generally produces some visual feedback on a computer screen, for example, motion of a cursor or indicator along a scale (Lawless & Heymann, ). On the other hand, the response device of the time–intensity evaluation system developed by Gotow and colleagues (Gotow et al, ) is a load cell connected to a spring, string and steel ring. Movement of the response device produces not only visual feedback on the computer screen as motion of an indicator along a linear scale, but also kinetic feedback on the index finger operating the ring.…”

“…The third aim is to provide an exercise trial under experimental conditions similar to those of the test trials (Harper & McDaniel ). Gotow et al (, ), who reported time–intensity evaluation of bitterness and retronasal aroma of coffee beverages by untrained panelists, used a warm‐up sample for the third reason. However, they did not investigate whether the use of a warm‐up sample stabilizes performance in time–intensity evaluation.…”

Comparison of Temporal Profiles among Sucrose, Sucralose, and Acesulfame Potassium after Swallowing Sweetened Coffee Beverages and Sweetened Water Solutions

“…The structure of this system was detailed by Gotow and colleagues [28,32]. However, to improve the portability of this system, we changed how the voltage output from the load cell was processed.…”

“…Participants also performed a time-intensity evaluation of sweetness using sucrose-sweetened, sucralose-sweetened, and acesulfame K-sweetened water solutions as control samples. Gotow and colleagues [28] developed a time-intensity evaluation system for untrained panelists, which was used in this study.…”