Odour extract dilution analysis

Twenty-nine odour-active compounds were detected by using aroma extract dilution analysis (AEDA) [60]. The results of AEDA together with GC-MS analysis showed ethyl 2-methylbutanoate (described as fruity flavour), followed by methyl 2-methylbutanoate and 3-methylbutanoate (fruity, apple-like), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (sweet, pineapple-like, caramel-like), d-decalactone (sweet, coconut-like), l-( ,Z)-3,5-undecatriene (fresh, pineapple-like), and a unknown compound (fruity, pineapple-like) as the most odour-active compounds. 

Grosch, W. 1994. Determination of potent odourants in foods by aroma extraction dilution analysis (AEDA) and calculation of odour activity values (OAVs). Flavour Fragrance J. 9 147-158. 

The volatiles of fresh leaves, buds, flowers and fruits were isolated by solvent extraction and analysed by capillary gas chromatography-mass spectrometry. Their odour quality was characterized by gas chromatography-olfactometry—mass spectrometry (HRGC-O-MS) and aroma extract dilution analysis (AEDA). In fresh bay leaves, 1,8-cineole was the major component, together with a-terpinyl acetate, sabinene, a-pinene, P-pinene, P-elemene, a-terpineol, linalool and eugenol. Besides 1,8-cineole and the pinenes, the main components in the flowers were a-eudesmol, P-elemene and P-caryophyllene, in the fruits (EJ-P-ocimene and biclyclogermacrene, and... 

Odor-active components in cheese flavor, many of which are derived from milk lipids, can be detected using GC-olfactometry (GC-O). GC-0 is defined as a collection of techniques that combine olfactometry, or the use of the human nose, as a detector to assess odor activity in a defined air stream post-separation using a GC (Friedich and Acree, 1988). The data generated by GC-0 are evaluated primarily by aroma extract dilution analysis or Charm analysis. Both involve evaluating the odor activity of individual compounds by sniffing the GC outlet of a series of dilutions of the original aroma extract and therefore both methods are based on the odor detection threshold of compounds. The key odourants in dairy products and in various types of cheese have been reviewed by Friedich and Acree (1988) and Curioni and Bosset (2002). 

Guth, H. and Grosch, W. 1993. Identification of potent odourants in static headspace samples of green and black tea powders on the basis of aroma extract dilution analysis (AEDA). Flavour Fragrance J. 8 173-78. 

P. Etievant, L. Moio, E. Guichard, D. Langlois, 1. Lesschaeve, P. Schhch, and E. Chamhellant, Aroma extract dilution analysis (AEDA) and the representativeness of the odour of food extracts. Trends in Flavour Research (H. Maarse and D. G. van der Heij, eds.), Elsevier, Amsterdam, 1994, p. 179. 

In the case of AEDA, which is mostly applied 7777, the result is expressed as flavour dilution (ED) factor. The ED factor is the ratio of the concentration of the odorant in the initial extract in which the odour is still detectable by GCO [14, 15[. Consequently, the FD factor is a relative measure and is proportional to the OAV of the compound in air. As an example, the analysis of the aroma of the baguette cmst [16] will be discussed. After separation of the acidic fraction, the neutral/basic volatiles were investigated by AEDA. Results listed in Table 6.24 reveal 21 odorants in the FD factor range 32-512, of which 2-acetyl-1-pyrroline (no. 1), 2-ethyl-3,5-dimethylpyra-zine (no. 10) and (E)-2-nonenal (no. 17) showed the highest FD factors. 

---