Лако-красочные материалы — производство

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.

Each odour is smelled by the panellist, who then scores the perceived intensity of each odour character that she or he can detect (referring to the set of standard odour references for clarification if necessary), which results in a sensory profile for that odour. A minimum of at least 20 profiles is usually collected for each sample and an average profile is then calculated. A set of typical odour profiles is shown in Figure 8.3. These profiles show the differences in perceived intensity of 13 odour characteristics identified in seven perfume materials, and immediately it is possible to see that although all of the materials are floral or muguet in character, one material is far more fruity (cyclamen aldehyde) and another (Mayol®) is far more herbal than the other materials.

Sensory profiling techniques are designed to produce stable and reproducible data, but difficulties arise when trying to compare data obtained from different laboratories. Often the methods of sensory assessment differ and there is no universally accepted odour language or list of odour standards to clarify this problem.

Fragrance profiles are often presented as a series of complex tables or graphs from which patterns, order or exceptions need to be found. Looking at individual profiles it is possible to determine the main odour characteristics. Comparison with the other profiles establishes the main differences between them.

However, this sort of comparison becomes extremely complex when large numbers of perfumes are involved. Multivariate analysis methods are descriptive procedures that help in this process. These methods are used to model or describe data such that they can be more easily understood by the researcher and thus simplify data comparison. Sophisticated software now exists that makes this kind of analysis possible without it being necessary to understand fully the mathe­matical modelling involved in the analysis. However, to interpret and understand the results a basic understanding of the technique is necessary.