Flavors, HPLC analysis

Figure 7.5. HPLC analysis of sweetener, flavors, and preservative in a soft drink sample using gradient reversed-phase chromatography and UV detection. Chromatogram courtesy of PerkinElmer, Inc.

Flavors A Case Study on HPLC Analysis of Capsaicins GC... 

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

Final proof came after chemically detecting the actual carcinogen in milk from bracken-fed cows by HPLC analysis [114]. This point will be resumed later as it makes sense only after a deeper look into bracken bioactive chemistry in the following sections. Direct contact with bracken metabolites may result from other uses. For example, fresh bracken fronds are used in the northern Andes as wrapping of cheese to be smoked, in order to add flavor to the product. Some Wayuu Indians of the Perija Sierra in Western Venezuela bum the dry fronds with a limited air supply inside their huts to fend off mosquitoes. Some communities in Colombia use frond infusions as vermifugues. However, data is still missing to relate these applications to human cancer. But all the well... 

Apart from citrus oils, other essential oils have also been analyzed by means of LC, such as the blackcurrant bud essential oil [100]. The latter was fractionated into hydrocarbons and oxygenated compounds and the two fractions were submitted to RP-HPLC analysis. Volatile carbonyls consist of some of the most important compounds for the blackcurrant flavor and, hence, were analyzed in detail. The carbonyls were converted into 2,4-dinitrophenylhydrazones and the mixture of 2,4-dinitrophenylhydrazones was separated into derivatives of keto acids and monocarbonyl and dicarbonyl compounds. Each fraction was submitted to chromatographic investigation. 

Revilla E, Martin-Ortega G, Ryan JM (2001) The application of HPLC analysis of anthocyanins to differentiate red grapes and wines. In Spanier AH, Shahidi F, Parliament TH, Mussinan C, Ho CT, Contis ET (eds) Food flavors and chemistry. Royal Society of Chemistry, London, pp 203-215... 

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. 

The high demand for authentic vanilla extract as a flavoring agent has resulted in frequent attempts at adulteration. An HPLC method for the quantitation of coumarins as an adulterant in a variety of vanilla flavorings, using a 10-yu.m /xBondapak Cl8 column with MeOH-HzO (40 60, v/v) as the mobile phase, was proposed (156). Phenolic analysis could be used further for the detection of mixtures of fruits in jams (157). The phenolics present in different commercial jams of apricot, plum, peach, strawberry, sour orange, apple, and pear have been compared and the characteristic compounds for each different jam identified for potential use as marker compounds. 

Flavor analysis see food analysis Food analysis 62-68 HPLC 231-234... 

Extracts of licorice root have also been used as a flavoring agent. Hlraga et al. (4 ) among others have developed an HPLC separation for the constituents in licorice. Because the numerous components in licorice vary considerably 1n polarity, a reverse phase C-18 column with a water/acetonitrlle gradient was employed. Nineteen components were identified. However, a three hour extraction coupled to the 60 m1n. analysis time probably makes this procedure too lengthy for routine use. 

The use of HPLC need not be limited to the analysis of nonvolatile flavor components. HPLC can be coupled with GC/MS to form an extremely powerful separation system. The unique separation properties of HPLC can be used to separate complex flavor mixtures to simplify later GC/MS separation and identification. This approach can be somewhat tedious to use in that a separate GC/MS run must be made for each HPLC fraction - but for very complex flavor systems there is often no other choice. Grob et al. (61 ) devised a direct transfer for HPLC fractions into a capillary GC to make this approach more convenient to use. They demonstrated the practical workability of the system by separating and Identifying two components in a toothpaste using both HPLC/GC and HPLC/GC/MS. 

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