Flavor dilution factor, measurement

These methods were developed to quantify and visualize the intensity of aroma as a chromatogram. A specific system named combined hedonic and response measurement (CHARM) was initially developed. Later on, aroma extract dilution analysis (AEDA) (Figure 3), a new method using a conventional GC-O system, was proposed. They share the same strategy aroma extract is diluted to a certain extent and then GC—O methodology is applied. In an AEDA procedure, if such a maximum extent of a dilution that allows the detection of a certain component is times diluted from the original sample, this component is referred to have a flavor dilution (FD) factor of . CHARM value corresponds to FD factor in a CHARM procedure. These values represent the contribution of the volatile the larger these values are, the more important they are considered as key components. 

Gas chromatography-olfactometry (GCO) has been used extensively for the identification of characteristic aroma conq)onents of foods (9,10). Aroma extract dilution analysis (AEDA) is a GCO technique in which serial dilutions (e.g. 1 3) of an aroma extract are evaluated by GCO. In AEDA, the highest dilution at which an odorant is last detected during GCO, so-called flavor dilution (FD) factor, is used as a measure of its odor potency (P). One potential drawback to AEDA is that the technique is limited to the analysis of components of intermediate and low volatility. To overcome this limitation, AEDA results have been con5>lemented by results of GCO of decreasing dynamic headspace (DHS) and decreasing static headspace (GCO-H) san5)les (70,77)... 

In AEDA, the assessor indicates whether or not an aroma can be perceived and notes the sensory descriptor. The result is expressed as the flavor dilution (ED) factor that corresponds to the maximum dilution value detected, i.e., the peak height obtained in CharmAnalysis. The FD factor is a relative measure and represents the odor threshold of the compound at a given concentration. The data are presented in an FD chromatogram (Fig. 5) indicating the retention indices (x-axis) and FD factors in a logarithmic scale (y-axis). AEDA has been proposed as a screening method for potent odorants as the results are not corrected for losses during isolation (7). 

The caramel-like smelling HDF has been established as a main contributor to the flavors of several processed foods (Table 17). In addition, it should be noted that in all these foods, on the basis of a high FD-factor, HDF was also by far the most important caramel-like smelling odorant. In the following, the strategy in the HDF precursor analysis will be shown using wheat bread crust, popcorn [88] and malt as the examples. Quantitative measurements were performed by using a stable isotope dilution assay (cf. Section 3.2.). 

Sweeteners can be classified into bulk and intense sweeteners (—>2.16). Bulk sweeteners need to be used in relatively large amounts to achieve the desired sweetness in contrast to intense sweeteners that are much sweeter and needed only in tiny amounts. The sweetness of individual bulk sweeteners is compared in Table 2.5. Sweetness is subjective. It is usually measured by preparing a 10% solution of the compound in water followed by a request to a panel of people to taste it. It is then diluted and tasted again, diluted and tasted again, and so on until the panel declares that the solution is no longer sweet. The perception of the sweet taste in food also depends on concentration, acidity, temperature, and the presence or absence of additives. But just as sweetness is affected by other factors, so it is that sweetness influences the perception of fruit flavors, sourness and bitterness as well. 

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