Sensory Analysis and Taste Modulation of Ketone Esters

Study Overview
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Brief Summary
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Ketone ester (KE) drinks are sold commercially in the USA and elsewhere (the FDA has accepted a GRAS (generally regarded as safe) notification on the KEs we propose to study). KE drinks can have beneficial effects on metabolism. Unfortunately, KE drinks have a strongly unpleasant flavor which can trigger rejection. The current study will generate data to help inform KE drink formulations with improved flavor. First stage, trained subjects will rate the intensity of various sensation qualities (e.g., bitter, sour, metallic, and astringent) from KE drinks to help understand the nature of the unpleasant flavor and the particular sensory systems involved (e.g., taste vs. smell). Then, subjects will taste KE drinks with and without various flavor modifiers. Subjects will be healthy adults (aged 21-45) without known food allergies.

Official Title
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Ketone Esters for Optimization of Operator Performance in Hypoxia Technical Volume (Sub-project: Sensory Analysis and Taste Modulation of the Ketone Ester)

Conditions
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Flavor Perception in Normal, Healthy Adults

Intervention / Treatment
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* Other: Flavor additive


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Good general health (self report) Men and women Age from 21 to 45 Exclusion Criteria: Current (or within the last four weeks) acute illness, such as cold or flu Currently active allergies Regular use of medication (over the counter or prescription), except for birth control. Any history of food allergy or sensitivity (particularly to KE drinks or MSG). Any history of sensitivity to 6-Propylthiouracil (bitter compound frequently used to assess individual differences in sensitivity to bitterness). Pregnant, nursing, or trying to become pregnant during the study (pregnancy can affect flavor perception) Chronic illness (any ongoing condition that is serious or required medical monitoring), including kidney problems, liver problems, cardiovascular problems (e.g., heart disease or high blood pressure), diabetes, HIV infection, or other ongoing illness). Diabetes or other metabolic issues could be important for safety as well as quality of data. History of taste problems (absent or abnormal sense of taste) Weigh less than 100 pounds (45.4 kilograms). This is to help ensure that the amount of KE drink consumed remains below the single serving in the GRAS (generally regarded as safe) notice which the FDA has accepted.

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Interventional Model Description: Within-subjects design (the same group of subjects will taste model KE drinks with vs. without added flavors), with order counter-balanced.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Effect of flavor modifiers<br>Intervention in the study: Subjects will taste model KE drinks with (control condition) and without (experimental condition) added flavors. Design is within-subjects (subjects will taste both the experimental and control drinks), with order counter-balanced across subjects. | Other: Flavor additive<br>* Various flavor additives will be tested (vs. no added flavor) to determine which show promise for making KE drinks taste less unpleasant<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Rated intensity profile | Rated intensity of taste qualities (e.g., sour, bitter) and mouth-feel (astringent) of model drinks, measured using the general Labeled Magnitude Scale (gLMS). In this implementation of the gLMS, scores will range from 0 (or no sensation) up to 100 (strongest imaginable sensation), with higher scores indicating stronger perceived intensity for the sensation in question. | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate the intensity of about 12 model drink samples during each study visit. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hedonic response | Ratings of how likely the flavor of each sample tasted would be to discourage use of a product with that flavor, assuming the rater otherwise wanted associated nutritional or performance benefits | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate the pleasantness of about 12 model drink samples during each study visit. | 
| Rated upper GI symptoms | Rated intensity of nausea, bloating, and heartburn, using a nine-point category scale (some bitter liquids can trigger mild to moderate feelings of nausea). Scores for each symptom range from 0 (none) to 8 (Unbearable), with mild (2), moderate (4), and severe (6) as labeled intermediate categories. | Through study completion (up to a year for a given participant, depending on how many drink samples the participant agrees to evaluate). Participants will rate upper GI symptoms after tasting about 12 model drink samples during each study visit. |