by Craig Warren, Ph.D.
Scientific Affairs Director, Sense of Smell Institute
August 27, 2007
Each year for the past 28 years the Association for Chemoreception Sciences (AChemS) holds its annual meeting in Sarasota Florida. The meeting draws most of its contributors and attendees from academic ranks with a smattering of people from industry. It has always surprised me that this meeting is so unappealing to my fragrance industry colleagues. Although research presented covers a broad range there is a wealth of information that is pertinent to fragrance. This year’s meeting featured 566 presentations, mostly poster, six symposia and a workshop on human pheromones. The industry symposium entitled: Recent Advances in Taste and Flavor, provided a good review of the ongoing academic research in this area. It was preceded by a symposium entitled: “Human Axillae: Why?” which reviewed underarm malodor, its generation and counteraction. The 2007 Science of Fragrance Award went to Dr. Jay Gottfried of Northwestern University in Chicago for his poster: Learning Modifies Neural Representations of Smell in Human Olfactory Cortex. The recipient of the Science of Fragrance Award is selected by the Award Committee working with its sponsor the Sense of Smell Institute (SOSI) and Theresa Molnar, Executive Director of the Institute. While the title of Dr. Gottfried’s poster sounds somewhat imposing, it boils down to a study of how external stimuli such as an advertisement affect the perception of fragrance. The poster is reviewed both below and on the SOSI website.
Of the 566 presentations I have culled out 17 presentations and one symposium that I feel will be of interest to my colleagues in the fragrance industry. I have classified the papers into the same categories used in the SOSI website virtual library:
- Odor Perception and the Brain
- Aroma-Chology: Human Behavior, mood and emotion
- Pheromones; Sensory testing
- Perception of Molecules and Mixtures
- Health and Disease
I would like to draw your attention to the workshop on human pheromones. The abstracts of the papers presented in this workshop combined with a Pub Med search of the authors of the abstracts will give you a very good feel for the state of this field based on its peer reviewed literature.
This year the book of abstracts for the program can be found on the AChemS website. If for some reason this URL doesn’t work, Google AChemS, visit the site map and go to “2007 Annual Meeting”. I mention this because unlike some meeting abstracts these are quite comprehensive and serve as a good starting place for further exploration. I have also referenced my comments to these abstracts.
Odor Perception and the Brain
To be effective fragrance advertisements need to stimulate our emotions. This is a given for most fragrance marketers. Dr. Jay Gottfried, winner of the 2007 Science of Fragrance Award, combined psychophysical techniques and functional brain imaging to show that a perception of a fragrance is not static but can be changed when it is paired with an emotional experience. (180. Learning modifies neural representations of smell in human olfactory cortex. Jay Gottfried. Dept Neurology, Cog Neurology & Alzheimer's Disease Center, Northwestern University, Chicago, IL, United States)
To be effective a fragrance ad should not be congruent with the odor type of the fragrance it is promoting. This finding is counterintuitive. Naomi Streeter and Theresa White have found that when odors are presented with redundant information the brain discards the olfactory information and retains the other information. This does not occur when the odor is incongruent with the accompanying information. This knowledge may be of value for the promotion of single note fragrances. (#495. Effect of Contextual Information on Short-Term Olfactory Memory. Naomi Streeter, Theresa White. Psychology, Le Moyne College, Syracuse, NY, United States.)
To the brain, single odorants and fragrances have one thing in common – complexity. Linda Buck, winner of the 2004 Nobel Prize in Physiology or Medicine, is now studying how the brain identifies odors. Both her previous and most recent work show that for single molecules and mixtures, the signal that the brain responds to is not the input from a single neuron but from a group of neurons. Odorant receptors are used combinatorial to encode odor identities. (#511. Deconstructing smell. Linda Buck. HHMI, Fred HutchinsonCancer Res Cen, WA, USA).
Jay Gottfried and coworkers using brain imaging techniques found that different smells produce different patterns of activation in the area deep inside the brain that processes smell, the piriform cortex. To the piriform cortex, coffee aroma has its own distinctive pattern as does rose and do all other aromas. (#562. Multivariate pattern analysis of odor quality in human piriform cortex. James Howard1, John-Dylan Haynes3, Jane Plailly1, Todd Parrish2, Jay Gottfried1. 1CNADC, Northwestern University, Chicago, IL, United States; 2Radiology, Northwestern University, Chicago, IL, United States; 3Human Cognitive and Brain Sciences, Max Planck Institute, Leipzig, Germany).
Mats Olsson and coworkers, using standard sensory techniques confirm what Linda Buck and Jay Gottfried have shown with their neurophysiology experiments. What Olsson and coworkers show is that perceptually a mixture of odor molecules has to be considered as a mixture of smells, not a mixture of molecules. (#339. Are we mixing odorants or odors? Malin Brodin1, Per Moeller2, Mats Olsson1. 1Dept. of Psychology, Uppsala University, Uppsala, Sweden; 2Dept. of Food Science, Copenhagen University, Copenhagen, Denmark).
In a sense, as Buck and Gottfried have shown, we have to think of the ingredients making up a fragrance not as single ingredients, not as a mixture of ingredients, but as a mixture of brain patterns that coalesce into a sensation. When the perfumer and marketer get it right the brain pattern produced by the combination of fragrance ingredients and advertisement elicits a very pleasurable sensation. Given the complexity of odor perception, the perfumer and flavorist is not going to be replaced anytime soon by a computer. However, research in this area may identify the brain patterns that correlate with pleasantness and we may also learn how to manipulate these patterns, and hence the sensation, with external stimuli such as advertisements.
Aroma-Chology: Human Behavior, Mood and Emotion
All floral odors are special but some work better than others. Previously Haviland-Jones and Wilson reported that floral odors elicited more positive emotion words than other kinds of pleasant odors. Floral bouquets elicited more positive social displays, like getting hugged, than other types of gifts. In this study the researchers compared floral odor types by looking at muguet, gardenia, jasmine, jasmine pale white, night blooming jasmine, ethyl alcohol and a no odor control. All floral aromas significantly reduced the use of anxious words in recalled recent memory, while in a recalled dream, jasmine and hyacinth elicited significantly more positive words than the other odors. The take home story is that some floral odors work better than others. (490. Dream and Recent Memory Narratives Reveal Differential Effects of Floral Odors. Patricia Wilson1, Caroline Coffield2, Estelle Mayhew2,Jeannette Haviland-Jones2. 1Psychology, La Salle University, Philadelphia, PA, United States; 2Psychology, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States.)
Young woman prefer a fragrance that has a personal meaning to them. The researchers found that young woman prefer a fragrance that has a personal meaning to them. While I suspect that most marketers know this intuitively, it is nice to have it confirmed by a study. Personal meaning is a strong driver of liking. (532. The Nature of Fragrance Preferences in Young Women. Marie-Paule Bensoussan, Robin Freyberg Yeshiva University)
Chocolate improves workplace performance and mood. Brian Raudenbush and coworkers found that visual and verbal memory were significantly higher for milk chocolate than for dark chololate or carob. In general, consumption of chocolate, either milk or dark was found to enhance cognitive performance. Carob, on the other hand, had no effect. (404. Effects of chocolate consumption on cognition, mood and workload. Rosanna Drake, Daniel Felbaum, Chris Huntley, Alex Reed, Lauren Matthews, Bryan Raudenbush. Psychology, Wheeling Jesuit University, Wheeling, WV, United States.)
If you are on a diet just try sniffing chocolate. In this study Raudenbush and coworkers found that sniffing chocolate or coffee enhanced cognitive ability and clerical work performance. (489. Differential effects of chocolate and coffee scents on enhancing cognitive ability and clerical office work performance. Daniel Felbaum, Justin Schmitt, Kristen Koval, Bryan Raudenbush. Psychology, Wheeling Jesuit University, Wheeling, WV, United States.)
Peppermint reduces smoking craving. The study showed that a peppermint inhaler reduced smoking craving but not as much as an actual cigarette. For people committed to quitting smoking a peppermint inhaler may prove useful as part of their quitting strategy. In the very least, as previous studies have shown, it will increase their performance of a boring task. (551. Effects of peppermint scent on diminishing smoking cravings and withdrawal symptoms. Daniel Felbaum, Jared Bloom, Trevor Cessna, Rosanna Drake, Bryan Raudenbush. Psychology, Wheeling Jesuit University, Wheeling, WV, United States.)
And peppermint reduces pain. Raudenbush and students found that peppermint scent and high arousal visual images are equally effective distractions in reducing pain produced by a common laboratory method, a cold pressor pain task. (488. Comparison of visual vs olfactory distractions on pain threshold and tolerance. Robert Bayley, Peter D'Amore, Lindsay Coyne, Kathryn Repicky, Daniel Felbaum, Bryan Raudenbush. Psychology, Wheeling Jesuit University, Wheeling, WV, United States.)
Pheromones
Google “human pheromone” and you should get around 92,000 hits. This year’s AChemS meeting in comparison had eight papers on the subject. Five of the eight were presented in a symposium entitled “Odor Signaling in Humans. This is the real stuff since each of the presenters, Elisabeth Oberzaucher, Martha McClintock, Bettina Pause, Tim Jacob, and Ivanka Savic are actively involved in the field as peer reviewed researchers. For anyone interested in finding out what is going on in the peer reviewed science side of the field, I recommend the symposium abstracts (#306 - #311) and the pheromone category in the Sense of Smell Institute Virtual Library.
The androstenone receptor provides the first link between perception and function of an odorant receptor. It is common knowledge that the aroma of androstenone is detected as urinous by about 30% of the population, sweet, sandalwoody by 30%, with the remainder not able to smell the material. Leslie Vosshall and coworkers report the identification of the olfactory receptor that detects both androstenone and a related steroid, androstadienone. They have also identified two single nucleotide polymorphisms (near neighbors) that account for the population that detect androstenone as sweet and sandalwoody. (#110. Genetic variation in a human odorant receptor alters perception of sex steroid-derived odours. Hanyi Zhuang1, Andreas Keller2, Qiuyi Chi1, Hiroaki Matsunami1, Leslie Vosshall2. 1Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, United States; 2Laboratory of Neurogenetics & Behavior, The Rockefeller University, New York, NY, United States).
Androstadienone, the human pheromone, is found to increase testosterone levels in woman. Noam Sobel and coworkers measured salivary levels of cortisol and testosterone in woman while they smelled androstadienone and a control odor condition. As shown previously androstadienone increased physiological levels of arousal and maintained a higher positive mood. In addition, smelling androstadienone maintained significantly higher levels of cortisol and testosterone. Thus, a single component of human sweat modifies endocrine balance in women (#348. Hormonal changes induced by smelling the human chemosignal androstadienone. Claire Wyart1, Sarah Wilson1, Jonathan Chen1, Rehan Khan1, Noam Sobel1,2. 1Helen Wills Neuroscience Institute, UC Berkeley, Berkeley, CA, United States; 2Neurobiology, Weizmann Institute, Rehovot, Israel).
Sensory testing: Perception of molecules and mixtures
Structure activity Relationships. Noam Sobel’s group has now worked on this problem for several years and he is beginning to make some headway. Their measure of odorant activity is the glomeruli response pattern in mice. There are now online databases of these response patterns to a number of common odorants. Using DRAGON software, Sobel and coworkers have found a set of molecular descriptors that relate odorant structure to glomeruli response pattern. Their set of descriptors explains 22% of the variability. The best previous fit explained only 3%. (#371. A physico-chemical metric for olfaction. Rafi Haddad, Rehan Khan, David Harel, Noam Sobel. Dept. of Computer Science and Applied Math, The Weizmann Institute of Science, Rehovot, Israel).
A single molecular property is found to correlate with odorant pleasantness. Using Principle Component Analysis, Sobel and coworkers created a mathematical model of perceptual space for odorants and a corresponding physio-chemical space for their respective molecular structures. They found that the most important dimension for perceptual space was pleasantness and the most important for physio-chemical space was molecular compactness. They then used this information to predict the pleasantness of 27 novel molecules. The prediction was validated with three diverse cultural groups: Americans, Muslim Arab Israelis, and Jewish Israelis. This suggests that pleasantness may be related in part to a property of the molecule. (#545. Predicting odorant pleasantness from odorant structure: Crosscultural validation. Rehan Khan2, Chung-Hay Luk2, Adeen Flinker2,
Amit Aggarwal2, Hadas Lapid1, Rafi Haddad1, Noam Sobel1,2. 1Neurobiology, Weizmann Institute of Science, Rehovot, Israel; 2Neuroscience, UC Berkeley, Berkeley, CA, USA).
Health & Disease
New findings show that smell and taste ability are compromised in a significant portion of the general population. Hummel and coworkers measured taste and smell ability in a representative subset (n=1312; age 27-75 yrs) of the population. They found: a) About 5% of the population cannot smell, b) about 24% of the population have a pronounced smell problem, c) about 9% of the population did not recognize one or more of the 4 basic tastes, d) there was an age related decrease in ability to smell but not to taste, e) smoking decreased one’s smelling ability but not their ability to taste. Thus,smell and taste ability are compromised in a significant portion of the general population. (#559. An epidemiological study on the frequency of smell and taste impairment. Thomas Hummel1, Mechthild Vennemann2,3, Klaus Berger3. 1Smell & Taste Clinic, Dept. of ORL, Univ. of Dresden Medical School, Dresden, Germany; 2Dept. of Epidemiology and Social Medicine, Univ. of Münster, Münster, Germany; 3Dept. of Legal Medicine, Univ. of Münster, Münster, Germany).
Bourgeonal, a common muguet type perfume ingredient, may find use in screen for male infertility. Hummel and coworkers found that decreased sensitivity to the odorant Bourgenal correlates with idiopathic infertility. It appears that the human olfactory receptor hOR17-4 (human Olfactory Receptor 17-4) also plays a role in sperm chemotaxis and thus in fertility. In other words, human sperm also has the same receptor. Bourgeonal, incidentally is an aroma chemical that was originally developed by Quest International. It has a muget odor character and is in the same family as Lyral, Lilial, and Florosa. It was found that idiopathic infertile men tend to be less sensitive to Bourgeonal but not to other floral odors such as phenyethyl alcohol and helional. (#210. Olfactory perception of the odorant Bourgeonal by infertile and fertile men. Eva Kemper1, Petra Spornraft-Ragaller2, Hanns Hatt3, Thomas Hummel1. 1ORL, Smell & Taste Clinic, Univ. of Dresden,
Dresden, Germany; 2Dermatology, Univ. of Dresden, Dresden, Germany; 3Cell Physiology, Ruhr-Univ. Bochum, Bochum, Germany).
Givaudan researchers find a way to boost fruity aroma. Shilling and coworkers have found that the fruity note of an accord can be boosted by the addition of an enzyme inhibitor. The inhibitor blocks the action of cytochrome P450 an enzyme present in the human olfactory mucosa that oxidizes (breaks down) the molecules responsible for the fruity note. (350. Inhibitors of nasal enzymes influence the perceived quality of odorants
Boris Schilling1, Hans Gfeller1, Heinz Koch1, Thierry Granier1, Xinxin Ding2, Esther Locher1 1Givaudan Schweiz AG, 2Wadsworth Center). |
