Sweet threshold detection value

Threshold detection value, Ctsv (the lowest concentration of an aqueous solution that can still be perceived as being sweet). 

A persistent idea is that there is a very small number of flavor quaUties or characteristics, called primaries, each detected by a different kind of receptor site in the sensory organ. It is thought that each of these primary sites can be excited independently but that some chemicals can react with more than one site producing the perception of several flavor quaUties simultaneously (12). Sweet, sour, salty, bitter, and umami quaUties are generally accepted as five of the primaries for taste sucrose, hydrochloric acid, sodium chloride, quinine, and glutamate, respectively, are compounds that have these primary tastes. Sucrose is only sweet, quinine is only bitter, etc saccharin, however, is slightly bitter as well as sweet and its Stevens law exponent is 0.8, between that for purely sweet (1.5) and purely bitter (0.6) compounds (34). There is evidence that all compounds with the same primary taste characteristic have the same psychophysical exponent even though they may have different threshold values (24). The flavor of a complex food can be described as a combination of a smaller number of flavor primaries, each with an associated intensity. A flavor may be described as a vector in which the primaries make up the coordinates of the flavor space. 

Oxazoles have been found in relatively few cooked foods, although over 30 have been reported in coffee and cocoa, and 9 in cooked meat. Oxazolines have been found in cooked meat and roast peanuts, but not to any extent in other foods. 2,4,5-Trimethyl-3-oxazoline has been regularly detected in cooked meat [26], and when it was first identified in boiled beef [27] it was thought that the compound possessed the characteristic meat aroma however, on synthesis it was shown to have a woody, musty, green flavour with a threshold value of 1 mg/kg [28]. Other 3-oxazolines have nutty, sweet or vegetable-like aromas and the oxazoles also appear to be green and vegetable-like [28]. The contribution of these compounds to the overall aroma of heated foods is probably not as important as the closely related thiazoles and thiazolines. 

In order to study the influence of the pH value on the sweetness enhancing effect of the novel Maillard reaction product, binary mixtures of the tasteless alapyridaine and the sweet tasting compounds glucose, saccharose, or L-alanine were sensorially evaluated in a triangle test using water with pH 5.0, 7.0 and 9.0, and the sweet detection thresholds determined were compared to the threshold concentrations of aqueous solutions containing the sweet tastants alone (Table I). 

A great many substances are known to produce the sensation of sweetness but, although this quality must stem from particular features of their chemical structure, it has not, so far, been possible to determine what these are. Most sugars and sugar derivatives have a sweet taste but so do many other totally unrelated compounds. Since the chemical basis of sweetness is unknown it is not possible to measure the property by scientific means and methods of sweetness measurement are necessarily subjective and include (1) equal sweetness matches in which the concentration that produces a sensation equivalent to that of a standard solution, usually sucrose, is determined and (2) threshold measurements, which involve finding the lowest detectable concentration of sweetener. Approximate relative sweetness values are given in Table 10.10 but there are, in addition, certain qualities of sweetness that are not easy to define. Some sweeteners lack the clean clear taste of sucrose and some have an unpleasant aftertaste. 

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