Chemesthesis and bitterness of natural and synthetic anti-inflammatory stimuli
Open Access
- Author:
- Bennett, Samantha Michelle
- Graduate Program:
- Food Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 23, 2012
- Committee Members:
- John E Hayes, Thesis Advisor/Co-Advisor
- Keywords:
- Chemesthesis
Bitterness
Ibuprofen
Olive Oil
Sensory Evaluation
Oleocanthal
Structure Activity Relationships - Abstract:
- Recently, Gibson’s ecological approach to classifying chemosensation has regained popularity. In his model, sensations are not classified on the basis of anatomy, but rather by the function they serve. The idea of a “chemofensor” complex expands the Gibsonian model to include chemesthetic sensations, as well as the classical bitter and sour tastes and rancid or rotten odors. This comes at a fitting time when more unpalatable, but healthful compounds are incorporated into our diet. In particular, the discovery of oleocanthal, a compound responsible for the pungency of virgin olive oils, has reopened issues of qualitatively assessing the characteristics of chemesthetic compounds. This thesis includes a discussion of the difficulties surrounding a human behavioral approach to measuring chemesthesis and bitterness, including perceptual similarity, temporal considerations, and sensory adaptation. Major experimental findings include: Study 1- Differences between sub-qualities of irritation from olive oil, ibuprofen, and capsaicin were quantified, implicating that olive oil shares qualities with both ibuprofen and capsaicin. Study 2- Behavioral response to compounds that share structural similarity to oleocanthal and ibuprofen were used to identify functional parts of the molecules as well as further characterize the oral sensations from commonly used pain medications. The data from tyrosol and oleuropein suggest the functional end of oleocanthal does not include the phenol group, but may require the aldehyde groups at the other end of the molecule. Study 3- Ibuprofen and naproxen are similar to each other (high irritation, some bitterness), but not acetaminophen (high bitterness, little irritation). This result mimics what would be expected structurally. Finally, in Study 4- we explored the role of fat for masking unpleasant oral sensations from ibuprofen in dairy products. We observed a modest reduction in irritation with increasing milk fat, but bitterness was unaffected. Unexpectedly, the reduction cannot be explained by partitioning into the fat phase, so more sophisticated analyses are needed to understand the binding mechanisms responsible.