Recent research indicates that fatty acids in food may have a taste. There is no lexicon to describe the sensation of the fatty acids, but participants frequently describe the sensation as bitter or sour. The proposed study will ask participants who have been screened for their ability to detect fatty acids to sort a variety of taste stimuli, including sweet, sour, salty, bitter, umami, and fatty acid tastes. Observing how the participants sort the stimuli will allow us to determine if the fatty acid taste is unique from other taste sensations.

Panelists will be screened for their ability to discriminate 0.5% linoleic acid emulsion from the blank using two sequential tetrad tests. Panelists will wear nose clips during the tests. Panelists must successfully complete both tetrads in order to qualify for the study. Panelists who qualify for the full study will provide written informed consent as well as data on their ethnic background, age, and their habitual fat intake. Heights and weights will be measured.

After completing the screening tests and the demographic questions, panelists will receive 15 samples (for the first group: "All tastes sorting") or 12 samples (for the second group: "Bitters sorting"). When panelists receive the samples, they will be instructed to put on nose clips and keep the clips on for the duration of the test. Participants will be provided with water for rinsing their mouths as well as a cup to spit the samples into after tasting. Panelists will be provided with more water and additional spit cups as necessary. Next, panelists will be instructed to: "Taste each sample, spit it into the spit cup, and rinse with water. Then, sort the samples into groups you believe are similar. Groups may contain as many or as few samples as you desire. You may have as many or as few groups as you desire." Once they have decided on their groups, they will write in a description for each group and rate the group for its overall similarity. After finishing this initial sorting task, if panelists have more than two total groups, they will be instructed to select the two groups they believe are most similar to each other and combine them. If panelists still have more than two total groups, they will be instructed to combine the two most similar groups again. This will continue until panelists only have two groups remaining. At each level, panelists will rate the new, combined group for its overall similarity on a visual analog scale, as before.

Data from this sorting task will be compiled in to dissimilarity matrices for each participant, showing how many groups it took them before each sample was combined with each other sample. This data will be analyzed to determine if the fatty acid samples are similar or unique in sensation from other taste qualities.

Inclusion Criteria:

• Healthy (self report), normal taste function

Exclusion Criteria:

• Medication that alters taste sensation, failed to detect 0.5% linoleic acid emulsion, allergic to dairy or nuts

Healthy men and women at least 18 years of age, not on any medication that alters taste sensation, and not allergic to dairy or nut products (samples contained a dairy protein and some sugars that were processed in facilities that also process nuts). Participants also had to pass a screening test to determine they could detect 0.5% linoleic acid emulsion compared to a blank solution.