The potent odorants were quantified in a sample of roasted Arabica coffee. On the basis of the results, 27 odorants were dissolved in an oil/water mixture. The flavor profile of the model obtained was very close to that of the real sample. In duo and triangle tests, the model was compared with models missing one or more odorants. These experiments indicated that 2-furfurylthiol, 4-vinylguaiacol, several alkyl pyrazines, furanones, acetaldehyde, propanal, methylpropanal, and 2- and 3-methylbutanal had the greatest impact on the coffee flavor.

No abstract

Genetic variation between naturally occurring populations provides a unique source to unravel the complex mechanisms of stress tolerance. Here, we have analysed O3 sensitivity of 93 natural Arabidopsis thaliana accessions together with five O3-sensitive mutants to acute O3 exposure. The variation in O3 sensitivity among the natural accessions was much higher than among the O3-sensitive mutants and corresponding wild types. A subset of nine accessions with major variation in their O3 responses was studied in more detail. Among the traits assayed, stomatal conductance (gst) was an important factor determining O3 sensitivity of the selected accessions. The most O3-sensitive accession, Cvi-0, had constitutively high gst, leading to high initial O3 uptake rate and dose received during the first 30 min of exposure. Analyzing O3-induced changes in stress hormone concentrations indicated that jasmonate (JA) concentration was also positively correlated with leaf damage. Quantitative trait loci (QTL) mapping in a Col-0 ¥ Cvi-0 recombinant inbred line (RIL) population identified three QTLs for O3 sensitivity, and one for high water loss of Cvi-0. The major O3 QTL mapped to the same position as the water loss QTL further supporting the role of stomata in regulating O3 entry and damage.

No abstract