Sensory analysis determination of qualities and defects

In 1966, Le Magnen proposed a designation of the organoleptic qualities of coffee. A choice of tests for the organoleptic valuation of coffee has been presented by Depledt (1968) and a sensory analysis of coffees and instant coffees has also been published by Van Roekel (1976). Vitzthum et al. (1976) were the first to use the sniffing -technique in the analysis of coffee volatiles. 

After an avalanche of analytical results, mainly with a view to discover a maximum number of new and typical constituents, some research groups focused their attention on the key constituents , arranging them in order of decreasing flavor contribution. This approach has been particularly conducted during the last two decades, thanks to the development of new concepts in sensory analysis and to the general tendency to improve the quality of foodstuffs. Moreover, the application of sensory analysis allowed, in collaboration with chemical methods, the identification of the compounds responsible for the aroma and, notably, determination of the intensity of individual odors of the fractions separated by chromatography. 

Reviews of the association of chemical and sensory aspects were published as early as 1965 by Wick and later, for instance, by Vernin (1981), who gave examples of odor-structure relationship. Different structures can be related to similar odors, similar structures to different odors, and similar structures to similar odors. A statistical treatment of data became necessary to correlate analytical results with those obtained by sensory analysis, as stated by Adda and Jounela-Eriksson (1979). Since then, correlation between sensory analysis and instrumental analysis has been the subject of important sessions of the Weurman Flavor Research Symposia, for instance in the chapters on Sensory science in flavor research (Weurman 5th Meeting, 1987) or Correlation between sensory and instrumental analysis (Weurman 7th meeting, 1993). 

2 ODOR ACTIVITY VALUE (OAV) OR ODOR UNIT OR AROMA VALUE OR FLAVOR UNIT 

Using odor units, Tressl (1989) found that some of the compounds that contribute the most are furfurylthiol (Section 5,1.128, sulfury), 4-hydroxy-2,5-dimethyl-3(2//)-furanone (Furaneol , Section 5, 1.100, caramel), 2-isobutyl-3-methoxypyrazine (Section 5,0.77, green), 2- and 3-methylbutanal (Section 5,C.12 and 5,C.13, malty, burnt), guaiacol (Section 5,H.33), and 4-vinylguaiacol (Section 5,H.36, smoky burnt). 

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