FLAVOR CHARACTERIZATION

The aroma of fmit, the taste of candy, and the texture of bread are examples of flavor perception. In each case, physical and chemical stmctures ia these foods stimulate receptors ia the nose and mouth. Impulses from these receptors are then processed iato perceptions of flavor by the brain. Attention, emotion, memory, cognition, and other brain functions combine with these perceptions to cause behavior, eg, a sense of pleasure, a memory, an idea, a fantasy, a purchase. These are psychological processes and as such have all the complexities of the human mind. Flavor characterization attempts to define what causes flavor and to determine if human response to flavor can be predicted. The ways ia which simple flavor active substances, flavorants, produce perceptions are described both ia terms of the physiology, ie, transduction, and psychophysics, ie, dose-response relationships, of flavor (1,2). Progress has been made ia understanding how perceptions of simple flavorants are processed iato hedonic behavior, ie, degree of liking, or concept formation, eg, crispy or umami (savory) (3,4). However, it is unclear how complex mixtures of flavorants are perceived or what behavior they cause. Flavor characterization involves the chemical measurement of iadividual flavorants and the use of sensory tests to determine their impact on behavior. 

Human perception creates difficulty ia the characterization of flavor people often, if not always, perceive flavors differently due to both psychological and physiological factors. For example, certain aryl thiocarbamates, eg, phenylthiocarbamide, taste exceedingly bitter to some people and are almost tasteless to others (5). This difference is genetically determined, and the frequency of its occurrence differs from one population to another 40% of U.S. Caucasians are nontasters, whereas only 3% of the Korean population caimot perceive the strong bitter taste of the aryl thiocarbamates (6). Similar differences were found ia the sense of smell for compounds such as menthol, carvone, and ethyl butyrate (7). 

Sensory perception is both quaUtative and quantitative. The taste of sucrose and the smell of linalool are two different kinds of sensory perceptions and each of these sensations can have different intensities. Sweet, bitter, salty, fmity, floral, etc, are different flavor quaUties produced by different chemical compounds the intensity of a particular sensory quaUty is deterrnined by the amount of the stimulus present. The saltiness of a sodium chloride solution becomes more intense if more of the salt is added, but its quaUty does not change. However, if hydrochloric acid is substituted for sodium chloride, the flavor quahty is sour not salty. For this reason, quaUty is substitutive, and quantity, intensity, or magnitude is additive (13). The sensory properties of food are generally compHcated, consisting of many different flavor quaUties at different intensities. The first task of sensory analysis is to identify the component quahties and then to determine their various intensities. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Flavor Intensity. In most sensory tests, a person is asked to associate a name or a number with his perceptions of a substance he sniffed or tasted. The set from which these names or numbers are chosen is called a scale. The four general types of scales are nominal, ordinal, interval, and ratio (17). Each has different properties and allowable statistics (4,14). The measurement of flavor intensity, unlike the evaluation of quaUty, requires an ordered scale, the simplest of which is an ordinal scale. 

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Flavor characterization Flavor compounding Flavor enhancer Flavor-filled capsules Flavoring agent Flavoring agents... 

Taste and Odor. The measurement of taste and odor is somewhat subjective and depends on the personal judgements of individuals. Panels of not less than five observers, and preferably more than ten, are used. The sample is diluted with odor-free water until a ratio at which the odor is just perceptible is determined this ratio is called the threshold odor number (TON). A similar method is used to detect a distinct taste in water (see Flavor characterization). ... 

Diethyl sulfite reaction, 10 530 Diethyltoluenediamine (DETDA), 25 197 Dietzeite, 6 471t Difasol process, 26 899 Difenzoquat, 13 322 Difference spectroscopy, 14 236 23 144 Difference tests, in flavor characterization, 11 512... 

Taylor, A.J., Sivasundaram, L.R., Linforth, R.S.T., Surawang, S. (2003) Time-resolved head-space analysis by proton-transfer-reaction mass-spectrometry. In Deibler, K.D., Delwiche, J. (eds) Handbook of Flavor Characterization. Sensory Analysis, Chemistry and Physiology. Dekker, New York, pp 411-422. 

Sweetened, low-alcohol wines are a difficult challenge to the home winegrower. It is simple to add the sugar but difficult to treat the wine so that the added sugar will remain unattacked by yeast or bacteria without having the treatment damage the flavor of the wine. Cloudy sediments, gas, and odd off-flavors characterize too many of these wines produced by home winegrowers. 

Flavor characterization Meaty octapeptide and other peptides Meat... 

Adedeji, J., Hartman, T.G. and Ho, C. (1993) Flavor characterization of different varieties of vanilla beans. Perfumer and Flavors 1 8, 11 5-133. 

Preininger, M., Ullrich, F. (2001) Trace compound analysis for off-flavor characterization of micromiUed milk powder. In Leland, J.V., Schieberle, P, Buettner, A. Acree, T.E. (eds.) Gas Chromatography-Olfactometry, ACS Symposium Series 782,pp. 46-61... 

The main volatiles in wines are the higher aliphatic alcohols, ethyl esters, and acetates formed from yeasts during fermentation. Acetates are very important flavors characterized by fruity notes, C4-Ci0 fatty acid ethyl esters manly confer fruity scents to the wine. Other wine aroma compounds are C6 alcohols, such as 1-hexanol and cis- and trans-3-hexen-l-ol, 2-phenylethanol, and 2-phenylethyl acetate. Contents of these compounds in wine are linked to the winemaking processes used fermentation temperature, yeast strain type, nitrogen level in must available for yeasts during fermentation, clarification of wine (Rapp and Versini, 1991). Much literature on the wine aroma compounds was reported in reviews by Schreier (1979) and Rapp (1988). 

Hartman T.G., Lech J, Karmas K., Salinas J., Rosen R.T. and Ho C.T. (1993) Flavor characterization using adsorbent trapping-thermal desorption or direct thermal desorption-gas chromatography and gas chromatography-mass spectrometry. 16 th I FT Basic Symp. Ser., New-Orleans, June 19-20, 1992. Ho Manley, Eds Flavor Measurement. Marcel Dekker, New York, pp. 37-69. 

Saffron, production, 66 Saffron flavor characterization using aroma extract dilution analysis aroma-active components, 74-78 detection of aroma-active component using OC-olfactometry, 67 experimental procedure, 67-68 volatile components, 68-74 Safranal, role in flavor, 66-78 Scmivolatile components in powdered turmeric, characterization using direct thermal extraction GC-MS, 80-96 Shallot, contribution of nonvolatile sulfur-containing flavor precursors to flavor, 53-63... 

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