Flavor precursors, analysis using

HERDERICH ET AL. Flavor Precursor Analysis Using HPLC—MSIMS 263... 

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.). 

The precursor analysis approach should now be seen as a useful complement to traditional methods of flavor analysis of fruits. The latter methods are often limited to the painstaking processes of isolation and identification of those trace constituents which are directly responsible for flavor. The precursor analysis approach takes advantage of the evidence provided by Nature vhen secondary metabolites, including flavor corpounds, are biochanically transformed and accumulated by the fruit. 

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... 

For fruits and their products, HPLC techniques for phenolics have been used to study the effect of processing, concentration, and storage on the phenolic composition of juices as well as a potential precursor for an off-flavor compound in juices. Phenolic analysis has been further applied to the detection of economic adulteration and especially to verify the authenticity of fruit juices. This is especially important when cheaper fruits can be added to more expensive ones in a fraudulent manner. In most fruits, the nonanthocyanin flavonoids consist mainly of flavonols and flavanols, with trace amounts of flavones. Glycosides are the predominant forms present. These most often are separated by reversed-phase HPLC on Cl8 columns with gradients consisting of acidified H20 and ACN, MeOH, or EtOH. 

In 1986, a review of the analysis of meat volatiles by Shahidi and colleagues (10) listed 995 compounds that have been found in meat. Mechanistic studies that have combined various amino acids and sugars have predicted the presence of even more compounds that have yet to be observed (77). The formation of flavor-producing compounds results from the complex interaction of numerous precursors and treatments. Some factors involved in beef flavor production are diet, postmortem aging, storage time and temperature, and cooking method. Additionally, it has recently been shown by Block et al. (72, 13) and others (74) that the method used to analyze flavor compounds may, in the process, create new flavor compounds. 

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