Aroma classification

Mocker, J., Wailzer, B., Buchbauer, G. and Wolschann, P. (2002b) Bayesian neural networks for aroma classification./. Chem. Inf. Comput. Sci., 42, 1443-1449. 

In 2008 Borah et al. [38] proposed that Neural Network based E-Nose, comprising of an array of four tin-oxide gas sensors, can assist tea quality monitoring during quality grading, principal component analysis (PCA) was used to visualise the different aroma profiles. In addition, K-means and Kohonen s self organising map (SOM) cluster analysis was done, multi layer Perceptron (MLP) network, radial basis function (RBF) network, and constructive probabilistic neural network (CPNN) were used for aroma classification [38]. 

We illustrate the application of support vector machines for aroma classification using as our example 98 tetra-substituted pyrazines (Figure 52) representing three odor classes, namely 32 green, 23 nutty, and 43 bell-pepper. The prediction power of each SVM model was evaluated with a leave-10%-out cross-validation procedure. This multiclass dataset was modeled with an one-versus-all approach. 

Lammertyn, J., Veraverbeke, E.A., Irudayaraj, J. (2004) zNoseTM technology for the classification of honey based on rapid aroma profiling. Sens. Actuators B 98 54-62. 

There are two fundamental classifications of flavors (1) natural, and (2) synthetic or artificial. Prior to die early beginnings of organic chemistry (circa 1828). all flavors, essences, aromas, and like substances were derived from naturally occurring materials. 

Table 3-10 Aroma and Structure Classification of Browned Flavor Compounds...

Figure 3B.5 shows the odour profiles of three wines as obtained using the OAV classification scheme. The example illustrates the differences between three types of wine in terms of volatile components, which have been classified into seven aroma series. 

The preface to the T edition, also intended as a summary to guide the reader through the book, has in the majority retained its relevance for the present edition. The already extensive survey of our field of work is complemented by a number of new topics. Prof. W. Grosch provides the reader with a comprehensive survey of aroma analysis with a special emphasis on key odourants. Contributors from multinational food companies introduce a focus on final products in the section on applications. Additionally, the sector on non-natural flavors has been expanded to include the current state of the European chemical group classifications. 

Table 3. Classification of the status of a food additive (i.e. aroma) as a function of the nature of the raw material and process used in its manufacture... 

Spices are aromatic vegetable substances used to provide flavor and aroma. A convenient classification for spices might be the following (a) the tropical spices such as pepper and cinnamon, (b) herbs such as sage and rosemary, and (c) seed spices such as mustard and sesame [4]. 

S. Borah, E. L. Hines, M. S. Leeson, D. D. Diescu, M. Shuyan, J. W. Gardner, Neural network based electronic nose for classification of tea aroma. Sens. Instmmen. Food Qutd. 2(1), 7-14 (2008)... 

It is demonstrated that, in clustering analysis three distinct clusters are present for three samples. Using these data the classification model can be made and may be used for prediction of quality estimation of cardamom. Also the volatile chemical constituents responsible for aroma of these samples are available. So the chemical composition of cardamom can be predicted by the data set generated by E-Nose. 

Figure 5 Classification of 88 white wine samples of three varieties from five producers according to vintage by linear discriminant analysis - plot in the coordinates of two main discriminant functions (DF2 versus DF1) composed of 19 original variables (concentrations of volatile, aroma creating compounds). Explanation of symbols O denote the 1996 samples, x the 1997 samples, -i- the 1998 samples. Probability ellipses express the 95% probability level. (Reproduced with permission from Petka J, Mocak J, Farkas P, Balia B, and Kovac M (2001) Classification of Siovak varietal white wines by volatile compounds. Journal of the Science of Food and Agriculture 81 1533-1539 John Wiley Sons Ltd.)...

The term aromatic was originally used to classify benzene and its derivatives because many of them have distinctive odors. It became clear, however, that a sounder classification for these compounds would be one based on structure and chemical reactivity, not aroma. As it is now used, the term aromatic refers instead to the fact that benzene and its derivatives are highly unsaturated compounds that are unexpectedly stable toward reagents that react with alkenes. 

The odors of single chemical compounds (aroma chemicals) are very difficult to describe unequivocally. The odors of complex mixtures called compounds are often impossible to describe unless one of the components is so characteristic that it determines the odor or flavor of the composition. Although an objective classification is not possible, an odor can be described by adjectives such as flowery, fruity, woody, or hay-Uke, which will relate to natural occurring or other well-known products with such odors characteristics. 

In the first classification test, class +1 contained green aroma compounds and class —1 contained compounds with nutty or bell-pepper aroma. The best prediction statistics for each kernel type are linear, C nomial, degree 2, C = 1000, AC neural, C = 10, a = 0.5, b = 0, AC... 

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