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

Differences in time-intensity sensory profiles of sweet taste intensity of glucose between older and young adults

Background

To understand age-related changes in sweet taste perception in daily life, it is important to understand taste intensity at the suprathreshold level. Previous studies have attempted to characterize the temporal aspects of human taste perception in terms of time-intensity evaluations. The perception of dynamic taste intensity in older adults increases slowly for salty taste; however, there have been no previous studies on time-intensity sensory evaluation of sweet taste in older adults. We hypothesized that older adults perceive sweet taste intensity more slowly than young adults.

Methods

Fifty young and 40 older adults participated in the study and glucose solutions of 0.6 M and 1.5 M were used as stimuli. The study comprised two experiments: (1) a cup tasting test (static taste perception in the mouth), and (2) a time-intensity sensory evaluation, in which the solutions were presented using a custom-made delivery system. The intra-oral device was made to fit each participant's dentition. Further, the level of gag reflex was taken into consideration for each participant in the design of the intra-oral device. A suction tube was placed across the posterior tongue near the throat to remove solution and saliva. The solution delivery system was controlled by an original computer program.

Results

Older adults presented significantly different maximum intensity timing and slope for both concentrations compared with young adults (slope for 1.5 M, p < 0.01; others, p < 0.05). No significant differences were found between the older and young adults for reaction timing and maximum intensity.

Conclusion

We conclude that older adults perceived sweetness more slowly than young adults, and ultimately perceived almost the same intensity as young adults. This is the first reported characterization of the time-intensity profile of sweet taste intensity of glucose in older adults. Using a standardized system enabled us to assess and compare feedback on taste intensities among different age groups in real-time. Based on this, we recommend older adults "savor" to perceive sweet tastes at the same level experienced by young adults.

Retronasal sensory characterization of aroma compounds in Baijiu by detection threshold measurement, retronasal OAVs, and time-intensity evaluation

The retronasal aroma of Baijiu is closely related to its quality and consumer preference. Retronasal detection thresholds (RDTs) of 44 aroma compounds were determined in 46% v/v ethanol using a three-alternative forced-choice procedure, which varied widely and ranged from less than 0.02 to over 1,000,000 µg/L. Nineteen aroma compounds, including β-phenylethanol, 2,3,5,6-tetramethylpyrazine, dimethyl trisulfide, and 2-methyl-3-(methyldisulfanyl)furan, had RDTs lower than their orthonasal detection thresholds. Power function curves were used to establish correlations between RDTs and partition coefficients for five esters and four pyrazines (R2  = 0.9575, 0.9969, respectively). Twenty-nine aroma compounds had retronasal odor activity values >1 in a soy sauce aroma type Baijiu. Additionally, time-intensity (TI) results suggested that hexanoic acid, ethyl hexanoate, isoamyl acetate, 3-methyl-butanal, and nonanal contributed to a "burst-aroma" of Baijiu. Conversely, TI results attributed the "after-odor" of Baijiu to dimethyl trisulfide, methional, 2,3,5,6-tetramethylpyrazine, β-phenylethanol, and other compounds. PRACTICAL APPLICATION: This manuscript provides comprehensive information on the retronasal sensory characteristics of aroma compounds in Baijiu. The results obtained may help understand the contribution of aroma compounds to retronasal aroma perception during Baijiu tasting and give helpful information to the Baijiu industry regarding quality control.

A Timely Application-Temporal methods, past, present, and future

Eating is a dynamic experience, and temporal sensory methods have been proposed to document how products change over the course of consumption or use (nonfood). A search of online databases yielded approximately 170 sources related to temporal evaluation of food products that were compiled and reviewed. This review summarizes the evolution of temporal methodologies (past), offers guidance in selecting appropriate methods (present), and provides insights into the future of temporal methodologies in the sensory space. Temporal methods have evolved to document a variety of characteristics in food products including how the intensity of a specific attribute changes over time (Time-Intensity), which specific attribute is dominant at each time during evaluation (Temporal Dominance of Sensations), which attributes are present at each time point during evaluation (Temporal Check-All-That-Apply), and many others (Temporal Order of Sensations, Attack-Evolution-Finish, and Temporal Ranking). In addition to documenting the evolution of temporal methods, this review considers the selection of an appropriate temporal method based on the objective and scope of research. When choosing a temporal method, researchers should also consider the selection of panelists to perform the temporal evaluation. Future temporal research should focus on validation of new temporal methods and explore how methods can be implemented and improved to add to the usefulness of temporal techniques for researchers.

Differences in dynamic perception of salty taste intensity between young and older adults

In super-aged societies, high salt intake substantially increases the risk of stroke and cardiovascular disease. Perceived low salty taste often prompts the addition of table salt to food. However, it remains unclear how older adults perceive the nature and intensity of salty taste in the mouth and brain. We compared the perceptions of salty taste intensities of older adults with those of young adults. Participants were 74 healthy adults: 31 older (age, 60–81 years [65.0 ± 5.5 SD]) and 43 young (age, 21–39 years [25.0 ± 3.6 SD]). Our research project comprises three sequential experiments. This article reports on the first two, which were (1) static and (2) dynamic sensory evaluations of taste perceptions in the mouth. Participants assessed the taste of 0.3 M and 0.5 M sodium chloride solutions in two types of sensory evaluations: (1) a cup tasting test, in which they sipped the solution from cups, spat it out, and rated static salty taste intensity, and (2) a time-intensity sensory evaluation, in which the solutions were delivered to participants’ tongues through a custom-made delivery system while they recorded dynamic taste intensities on a hand-held meter. Older adults perceived significantly lower taste intensities than young adults (p = 0.004 and p < 0.001 for 0.3 M and 0.5 M, respectively). Reaction timings for both solutions did not differ, but the slopes for both concentrations were significantly lower for older adults than for young adults (p < 0.001). Using a standardized system allowed us to evaluate and directly compare real-time feedback on taste intensities according to age. This study is the first to characterize the time-intensity profiles of salty taste intensity in older adults. Our findings show that older adults do not take longer to recognize a salty taste, but their perception of taste intensity slowly increases, and yet remains lower than that of young adults. This suggests that older adults should be aware of the tendency to add more salt to their food to compensate for their low perceptions of salty taste. We would like to suggest them to savor and chew sufficiently during eating to optimize the perceived salty taste. Furthermore, our results offer a reference for ordinary citizens’ taste-intensity perceptions; our standardized system could be usefully integrated into clinical follow-up examinations and treatments.

Multi-Sip Time⁻Intensity Evaluation of Retronasal Aroma after Swallowing Oolong Tea Beverage

In most cases, a meal cannot be finished with a single bite and sip. During eating and drinking, consumers receive dynamic food perceptions from sensory attributes in foods. Thus, we performed multi-sip time–intensity (TI) evaluation of sensory attribute. In each of ten trials, the participant evaluated continuously the intensity of retronasal aroma for 60 s after swallowing oolong tea. We compared the TI parameters (I_max: maximum intensity, T_max: time point at which intensity reached the maximum value, AUC: area under the TI curve, D_plateau: duration between the first and last time points with values exceeding 90% of the maximum intensity, R_inc: rate of intensity increase between the first time points with values exceeding 5% and 90% of the maximum intensity, and R_dec: rate of intensity decrease between the last time points with values exceeding 5% and 90% of the maximum intensity) and TI curves among the ten trials, and approximated each TI curve with an exponential model. Some TI parameters (I_max, T_max, AUC, and R_inc) differed significantly between the first and subsequent trials. The TI curve was significantly lower in the first trial than in the subsequent trials, and TI curve during the time from starting the evaluation to reaching maximum intensity was significantly lower in the second trial than in the subsequent trials. The time constant of the fitted exponential function revealed that the decay of retronasal aroma intensity was slightly faster in the second through fourth trials than in the first and the fifth through tenth trials. These results indicate that olfaction might be more perceptive while consumers sip a cup of the beverage.