Odour sensory testing

ANONYMUS 1982. On target values for odour control by sensory test method. Japan environment summary. Vol. 10, no 9. 

Odour can be described using a number of different dimensions, each of which can be measured using different sensory tests threshold, intensity and quality. 

What does this odour smell like The tests used to describe odour quality are known as odour profiling tests. These are the most complex of the sensory tests and, to ensure good quality, accurate and reproducible data are only carried out by highly trained and experienced sensory panellists. 

Use of Odour Thresholds in Sensorial Testing and Comparisons with Instrumental Analysis. Proc. int. Symp. Aroma Research, Zeist, p. 121. Wageningen Pudoc. 1975. 

Comprehensive studies of this technique have been made at JTI and KI. In one of these studies comparisons were carried out between different spreading and burial methods for pig manure. The odour determinations were made in a mobile laboratory especially constructed for sensory measurements of air pollutants (1). The laboratory mainly consists of an airconditioned test-room with three exposure hoods. Fig. 3 shows a general outline of the mobile laboratory with the sampling equipment. 

To test the potential of PLS to predict odour quality, it was used in a QSAR study of volatile phenols. A group of trained sensory panelists used descriptive analysis (28) to provide odour profiles for 17 phenols. The vocabulary consisted of 44 descriptive terms, and a scale fiom 0 (absent) to S (very strong) was used. The panel average sensory scores for the term sweet were extracted and used as the Y-block of data, to be predicted from physico-chemical data. 

In the case of pineapples, the 12 odorants listed in Table 16.7 were dissolved in water in concentrations equal to those determined in the fruit [50]. Then the odour profile of this aroma model was evaluated by a sensory panel in comparison to fresh pineapple juice. The result was a high agreement in the two odour profiles. Fresh, fruity and pineapple-like odour notes scored almost the same intensities in the model as in the juice. Only the sweet aroma note was more intense in the model than in the original sample [50]. In further experiments, the contributions of the six odorants showing the highest OAV (Table 16.7) were evaluated by means of omission tests [9]. The results presented in Table 16.8 show that the omission of 4-hydroxy-2,5-dimethyl-3(2H)-furanone, ethyl 2-methylbutanoate or ethyl 2-methylpropanoate changed the odour so clearly that more than half of the assessors were able to perceive an odour difference between the reduced and the complete aroma model. Therefore, it was concluded that these compounds are the character-impact odorants of fresh pineapple juice. 

The objective of this chapter is to give an overview of the processes and problems related to prints on food packages, dealing primarily with the components of inks and their possible migration into the foodstuff. Sensory (odour and taint) aspects and testing will also be covered and statutory requirements will be discussed. 

Sensory analysis is a subjective sensation by the sense organs. Assessors perform sensory analyses. For a packaging material, transfer of taint is the critical sensory property from a legal point of view. Odour is less significant, but equally important as a marketing consideration. A panel of trained assessors evaluates the sensory properties. The number of assessors is based on the sensitivity desired for the test fewer assessors result in less statistical reliability. A well-trained panel will give consistent results. 

After 28 days a final test comprising a toxicological test (LUR for all detected VOCs less than 10 and relevant compounds with concentrations more than 5 pg/m should be evaluated toxicologicaUy), TVOC test (less that 200 pg/m ) and a sensory irritation test (odour/perceived air quality evaluation should have been performed). A label is given if all tests are passed. 

Another labelling scheme is the indoor climate labelling scheme, in which building products are tested for their emission of VOCs and by a sensory evaluation of the emissions as a safety measure [62]. The parameter used for evaluation and as a criterion is the time required for the emission of VOCs of concern to decay to the point where their (modelled) room concentrations are below their indoor relevant values. These are based on 50% of either odour-threshold values or airway-irritation estimates. 

A range of soaps was profiled by the sensory panel and the results were analysed to give a two-dimensional map, showing the relative similarities in odour character of the perfumes tested (Figure 8.5). 

The complicated olfactory system in humans and animals can detect and differentiate the presence of an odour even at trace levels [187]. Sensory evaluation is one of the important parameters for environmental monitoring, quality assessment for food, wine and beverages, and clinical diagnosis, as well as for the control of many cosmetics and fermentation processes [188-190]. Typically, sensory evaluation in odour as well as food/ wine testing is performed by a panel of well-trained professionals based upon their sense of smell, taste, experience and mood. However, the human olfactory system is very sensitive but not selective. 

Discrimination tests, such as pair comparison or triangular tests, have been widely used in order to evaluate the sensory abilities of children. Discrimination tests in the olfactory domain have indicated a lower ability to discriminate odours in 2- to 4-year-old children compared to children over 5 years (Richman et al., 1995). Discrimination... 

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