Odor hedonics

Table VII presents the non-linear equations, for the four sets of data. Note that the non-linear equations always fit the results better than the linear equations do, in part because the more predictors one can use in the equation the higher will be the multiple correlation coefficient (multiple R). On the other hand, the equations also contain some significant non-linear (square) and occasionally significant interaction terms, suggesting that odor hedonics, like other taste and food hedonics, conform to a non-linear function of concentration, with a potential set of intermediate bliss points.

We can also inquire as to the sensitivity of odor hedonics to changes in the concentration. Do all odorants, despite their different qualities, behave similarly with respect to hedonics as they change concentration Does a 10 unit increase or decrease in concentration beyond the bliss point generate the same change in overall liking for each of the odorants. 

Specific scales may be used to rate the perception of intensity of (/) the malodor, and (2) the malodor along with an odorous material designed to modify the malodor. Rating scales may consist of numerical assignments to words, eg, from 0 = no odor to 10 = very strong odor. These same type of scales maybe used to describe both the hedonic acceptabiUty of the net result, ie, from 0 = very unpleasant to 10 = extremely pleasant, and the degree of modification, ie, from 0 = does not modify to 10 = complete elimination or cover-up. 

Four characteristics of odor are subject to measurement by sensory techniques intensity, detectability, character (quality), and hedonic tone (pleasantness-unpleasantness) (16). Odor intensity is the magnitude of the perceived sensation and is classified by a descriptive scale, e.g., faint-moderate-strong, or a 1-10 numerical scale. The detectability of an odor or threshold limit is not an absolute level but depends on how the odorant is present, e.g., alone or in a mixture. Odor character or qualit) is the characteristic which permits its description or classification by comparison to other odors, i.e., sweet or sour, or like that of a skunk. The last characteristic is the hedonic type, which refers to the acceptability of an odorant. For the infrequent visitor, the smell of a large commercial bread bakery may be of high intensity but pleasant. For the nearby resident, the smell may be less acceptable. 

Doty, R.L., Green, P.A., Ram, C. and Yankell, S.L. (1982) Communication of gender from human breath odors relationship to perceived intensity and pleasantness. Horm. Behav. 16, 13-22. Doty, R.L., Kligman, A., Leyden, J. and Omdorff, M.M. (1978) Communication of gender from human axillary odors Relationship to perceived intensity and hedonicity. Behav. Biol. 23, 373-380. 

Soussignan, R., Schaal, B., Marlier, L., and Jiang, T. (1997). Facial and autonomic responses to biological and artificial olfactory stimuli in human neonates re-examining early hedonic discrimination of odors. Physiol. Behav. 62, 745-758. 

Odors affect human behavior more than we realize. They are now appreciated as important in human health and disease. Above all, the powerful role of learning is impressive. Odors become associated with pleasant and unpleasant experiences and can retain their hedonic value lifelong. This applies to food, to social and sexual relationships, and to environments such as houses, workplaces, or landscapes. Writers rather than scientists have described such anecdotes. In Remembrances of Things Past, Marcel Proust evoked a flood of childhood memories by the taste of a madeleine dipped in lime-blossom tea. Jean-Paul Sartre tells in his autobiography Les Mots how the halitosis of his grade-school teacher became to him the odor of authority. 

However, a single GC-O run only is usually insufficient to distinguish between the potent odorants that most likely contribute strongly to an aroma and those odorants that are only components of the background aroma. Therefore, to improve the results, two methods, combined hedonic aroma response measurements (CHARM) analysis [4] and aroma extract dilution analysis (AEDA) [5, 6] have been developed. As discussed in Sect. 16.4 in both methods serial dilutions of food extract are analysed by GC-O. 

Industry has standardized procedures for the quantitative sensory assessment of the perceived olfactory intensity of indoor malodors and their relationship to the deodorant efficacy of air freshener products. Synthetic malodors are used for these evaluation purposes. These malodors should be hedonically associated to the reaT malodor, and must be readily available and of consistent odor quality. These malodors should be tested in various concentrations and be representative of intensities experienced under normal domestic conditions. Panelists are trained to evaluate malodor intensity and the degree of modification. 

The evaluation is performed either by a large untrained panel or by a smaller trained panel. As odor characteristics to be evaluated an intensity scale, a hedonic... 

Figure 8.3 Odor evaluation scales for (a) intensity (VDI 3882-1) (b) hedonic odor tone (VDI 3882-2) and (c) acceptance (Clausen etal., 1996 Clausen, 2000).

Odor intensity Hedonic odor tone Perceived air quality (decipol)... 

Special problems are related to odor measurement, its quantification and to odor policy (Frechen, 2000). Odors usually consist of many different compounds of very low concentrations that may exert synergistic or antagonistic effects. Four generally accepted dimensions of odor exist which include the concentration of odorants, the intensity of odor, its character, and its hedonic tone (i. e. its pleasantness or unpleasantness). It is extremely difficult to relate conventional analytical measurements (e. g. gas chromatographic determinations or sensor array measurements with an electronic nose ) to the intensity, character, and hedonic tone of an odor perceived by the human nose. 

Doty RL, Omdorff MM, Leyden J, Klingman A (1978) Communication of gender from human axillary odors Relationship to perceived intensity and hedonicity. Behav Biol 23 373-380... 

Regardless of the motivation, and whether it will be long lasting, the scientific aspects of this subject are important and worthy of study. The aroma or odor of food is an important part of the hedonic value of the food and thus becomes part of our food selection process. Since our nutritional state and well being are partially related to food selection, understanding the biological generation of aromas is not conducted only to satisfy the current need of the marketplace, but takes on an important scientific and nutritional role. 

We consume them directly, combine them with other foods directly or through cooking, convert them into sauces, etc. There seems to be no end to the creative way we utilize and consume fermented dairy products. The lesson is clear, we use these products because we enjoy their odor and taste. In the selection process, their nutritional value is secondary when compared to their flavor. Since food consumption is a necessary part of life, and in most societies food selection is primarily based on hedonics, then a priori, the biological origin of aromas is an important subject. 

Dravnieks, A. Contribution of molecular properties of odorants to the hedonic value of their odors. Paper presented at the 7th Symposium of the Sense of Smell, Cannes, France, 1972. 

In the past five years, the quantitative measurement of quality, intensity, duration and hedonics of flavors and fragrances has become important. The measurements are used both for comparison of new products to those on the market and for substantiation of performance claims. For this last measurement the use of naive panels which reflect the opinions of the potential consumer becomes important. Examples of the types of measurements needed are a) odor and flavor intensities of ingredients and finished products, b) substantivity of fragrances on skin and c) the effect of solvent on the odor intensity of a fragrance. Although the discipline of physical chemistry can be... 

Odorants. Twenty-eight odorants covering a large variety of odor character notes and a broad hedonic tone range (from isovaleric acid to vanillinj were used ... 

Improvements to the Model. Since other odor notes undoubtedly influence the scores of some selected odor notes, additional variables were added to the simple regression model above on a multiple stepwise regression analysis was conducted. For each odor note, the other candidate variables were all other 29 descriptor scores, and the hedonic tone of the hedonically lowest (least pleasant or most unpleasant) and highest components. ( )... 

Linear regression equations anchored to the mean of the component scores typically accounted for 50 percent of variance. Introduction of other odor notes and hedonic data to expand these by 4 additional variables increased the accounted for variance by about 10 percent occasionally more or somewhat less. 

Descriptive results from three field studies concerned with a possible association between genetical similarity with regard to the MHC and the hedonics of body odors as well as the degree of acquaintance yielded a similar pattern of results The similarity in class I HLA-A and HLA-B alleles appears to be associated with the hedonics of another person s body odor and with the degree of acquaintance or familiarity between persons. The direction of these associations appear to depend on whether the persons are of the same sex or of opposite sexes. Repeated measurements of the degree of acquaintance point to the conclusion that formation of groups and social choice between people may be influenced by their HLA-similarity. 

The three studies yielded a similar pattern of results The similarity in class I HLA-A and -B alleles appears to be associated with the hedonics of another person s body odor... 

By determining the hedonic odor effect, the emotional reaction initiated by an irritation to the sense of smell may be included. It should not be confused with the kind of smell (it smells like. ..) or with the odor intensity (it smells strong to Figure 18.1.8. Evaluation ofthe hedonic effect of an odor weak ). It may be determined not only for sample [VDI 3882/2]. " ... 

Blatt 2 Olfactometry - Determination of hedonic odor tone, September 1994. 

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