The largest differences found were between the two different varieties Catuai and Tipica. There were profound differences in their compositions: at 210 nm, Catuai shows a larger area for the HMW fraction, whereas Tipica shows a larger area at 280 nm. The results at 280 nm are particularly interesting; differences between the degrees of ripeness are visible for both coffee varieties, and clearly lower values were measured for the ripe beans than for the KU-57788 research buy unripe and half-ripe ones ( Fig. 3). The volatile profile of green coffee was investigated by analysing both the headspace of finely ground green coffee as well as of whole green beans. It was found that analysing the headspace above whole green beans

is more reproducible than when doing the same with ground green coffee. It is likely that volatile oxidation products of green coffee beans occurred with different intensities for different ground replicates and some compounds were even absent from certain chromatograms. There was no observable systematic trend to these differences in the ground green samples, such as stabilisation of headspace over a time period or degradation with time, therefore sampling above whole beans was used. This not only simplified the analysis of the sample, but also eliminated a processing step (grinding) that may have introduced some variance

between the replicates (e.g. particle size distributions) Everolimus price and potentially masked small but real differences in the compositions of the different samples. In total, 68 compounds were identified and peak areas were integrated. Three different types of behaviour for peak intensity were identified. (i) No clear trends between the degrees of ripeness, but relatively repeatable data between replicates. E.g. 1-hexanol showed the highest intensity in Tipica for half-ripe, whereas in Catuai the half-ripe beans had the lowest intensity of the three degrees of ripeness – Fig. 4a. (ii) Very different intensities between the two varieties, with possible but small differences dependent on the degree of ripeness. For example, higher intensity for 2,6-dimethyl pyridine was observed in Catuai beans ( Fig. 4b),

while the intensity for 2,3-butanediol was higher in Tipica beans ( Fig. 4c). (iii) Furfural ( Fig 4d) was differentiating between the ripeness levels of Catuai, whereas no differentiation was observed for Tipica. The unripe and Ergoloid half-ripe Catuai samples had higher furfural signals than the corresponding Tipica samples. In contrast, furfural signal was much lower in the ripe Catuai beans than in the ripe Tipica beans. In order to extract differences between samples across the two varieties and three degrees of ripeness, the various datasets were analysed by principal component analysis (PCA). A statistical analysis with PCA of the RP-HPLC data showed very good separation in the degree of ripeness especially along PC2 (24% loadings) for both the Catuai ( Fig. 5a) and the Tipica ( Fig. 5b) samples.