Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Nutrition, Dietetics, and Food Sciences


Charlotte P. Brennand


The effect of time on taste threshold was examined in 30 diabetics and 30 control subjects (ages 22-30) who had participated in a sensory study 14 years previously. Detection and recognition taste thresholds for sweet (sucrose), salty (sodium chloride), sour (citric acid), and bitter (quinine sulfate) were assessed using triangle testing. Food preferences related to concentration of the stimuli in model food systems were tested using a nine-point hedonic scale. Mashed potatoes were used as the carrier for different levels of salt. A beverage composed of water, sucrose, and citric acid was varied to measure preferences for sweet and sour tastes. Demographic, health status, and selected dietary and food consumption information were also obtained.

In the initial study, the diabetic group had higher detection and recognition thresholds for sweet, salty, and bitter stimuli than the control group. Although the control group still had lower thresholds for most of the stimuli (except for recognition of sour and salty), the majority of the diabetics either remained at their same taste sensitivity or improved their ability to perceive the stimuli over the 14-year period. With the exception of recognition of bitter by diabetics, both groups improved in their ability to identify taste sensations with age. Overall, the diabetic group became better at detecting sweet, sour, and salty taste stimuli between 1977 and 1991. They also became more sensitive to recognizing sweet and salty taste stimuli.

For each set of food samples, a significant relationship existed between rating and sample. Samples with moderate levels of sodium chloride, citric acid, or sucrose were the most preferred . There was not a significant difference between the diabetic and control groups in their rating of the samples. Diabetic and control groups did not rate the samples significantly different. Additionally, threshold was not related significantly with rating of mashed potato samples or beverage-sour solutions. However, sucrose recognition thresholds and preference for sucrose concentration in beverage-sweet solutions were significantly related. Subjects with higher threshold values tended to rate the samples with higher concentrations of sucrose higher.

There were no noteworthy correlations between the reported levels of salt consumption and salt thresholds, between sugar consumption and sucrose thresholds, nor between liking sour foods and citric acid thresholds.