High damascenone

Table 20.1 shows the detection thresholds of a number of perfume materials in air and in water. Note the tremendous range (from 0.002 parts per billion for beta-damascenone to 10,000 parts per billion for phenylacetic acid—both taken in water solutions), the large difference between optical isomers of the same substance (e.g., Nootkatone and alpha-damascone), and the large differences in thresholds reported by different investigators (e.g., benzaldehyde and vanillin). In substances with relatively high water solubility such as vanillin and ethyl vanillin, benzaldehyde, phenylethyl alcohol, and phenylacetic acid, the thresholds in water are very much higher than in air. In poorly water-soluble substances such as pinene and the macrocyclic musk cyclopentadecanolid, the reverse is true. The relative thresholds of a substance in different solvents indicate its performance in different application environments. Substances whose thresholds in water solution are much... 

Figure 2. Concentrations of cis-rose oxide, linalool, (E)-li-damascenone and wine lactone in different stages of wine making 1 = after pressing of grapes, 2 = after yeast fermentation, 3 = after malolactic fermentation, 4 = after maturing in high-grade steel...

Comparing the odor spectrum gas chromatograms of the three wines, in Figure 3, a general effect was observed. Floral, fruity compounds were the dominant odorants in the "no Brett" wine while rancid, plastic odors accounted for 1/3 or less of the odor activity in the "medium Brett" wine, the floral, fhiity compounds decrease to 1/2 or less of the odor activity while the rancid, plastic compounds increase to 2/3 in the "high Brett" wine, the rancid, plastic compounds were the dominant odorants while the floral, fhiity compounds were far less dominant. The floral odorant identified as 2-phenyl ethanol was the dominant compound in "no Brett" and "medium Brett" wines in the "high Brett" wine, it was equally as dominant as isovaleric acid and the unknown compound. The fiuity odorant B-damascenone was equally dominant among the three wines for this reason, it should not be considered as a contributor to "Brett" aroma. 

CIC The fatty aldehydes octanal, nonanal, decanal together with the corresponding fatty acids and their ethyl esters are responsible for the characteristic fatty aldehydic flavour of the skin. (E)-2-hexenal, hexanal and (E)-2-pentenal contribute to the refreshing character, supported by the high acidity of the juice. Methyl-2-methyl bu-tanoate, methyl-3-methyl butanoate and methyl hexanoate impart a fresh, fruity note, rounded off with traces of methyl benzoate, methyl salicylate and the sweet floral note of beta-ionone and damascenone. 

A bioassay for the precursor compound to p-damascenone, frartj-2,6,6-trimethyl-cyclohexa-1,3-dienyl- l-but-2-ene- 1-one, found in grape skins was developed based on the generation of free p-damascenone and the sensory technique charm. Thin layer, column, and high pressure liquid chromatography were used to separate the precursor from 80 kg of grapes, Vitis labruscana, Bailey cv. Concord. There was a 22,000 fold enrichment in the precursor in 3.7 g of isolate. 

Spadone et al. (1990) also identified aliphatic unsaturated aldehydes, long-chain 2-alkanones, lactones and esters which are only present in green coffee and would give the beans the characteristic soapy, fatty and fruity (coconut, peach, apricot) notes. They were the first authors to find (3-damascenone (Section 5,D.38) in raw coffee, a compound that resists roasting and contributes highly to the tea-like and fruity flavor of the beverage,... 

Despite their overall high abundance, the sesquiterpene hydrocarbons ( )-caryophyllene and )S-elemene were not detected by GCO and AEDA. This indicates that these compounds may play either no role or only a minor role in the overall aroma of O. sanctum. Results of AEDA (Table 1) indicate that eugenol cloves) is the predominant odorant in the essential oil, followed by jS-damascenone (floral, applesauce), 2-isopropyl-3-methoxypyr-azine (earthy, potato), and 1,8-cineol (minty, eucalyptus). The fact that eugenol and 1,8-cineol are key aroma components is not surprising and is supported by previous studies [1-9]. However, jS-damascenone and 2-isopropyl-3-methoxypyrazine had not been previously reported as components of O. sanctum. The AEDA procedure was conducted on the fresh herb to determine whether these latter components are indeed natural constituents of the herb or whether they are generated during the production of the... 

Differing intensity functions for volatiles account for a well-known phenomenon in GC-O some intensely smelling compounds disappear after a few dilution steps (e.g., vanillin), whereas others with a lower aroma intensity in the original extract have the highest FD factors. The sensory relevance of the latter is overestimated. ( )-P-Damascenone is a typical representative for such compounds, which are characterized by a relatively flat dose/intensity function. This is most likely why ( )-P-damascenone does not play a major role in the aroma of coffee, despite low threshold values (Table 12), i.e., high FD factors and OAVs. In other words, threshold concentration does not necessarily correlate with aroma potency. 

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