The decrease in the content of some of the CGAs compares well to data published in the literature. An indication of a drop in the di-CQAs ( Jham et al., 2001) as degree of ripeness increased (immature, ripe, overripe) has been reported. A similar observation was reported in another study ( Koshiro et al., 2007) examining unprocessed beans, where the authors reported a decrease in di-CQA and 5-CQA and an increase in 3-CQA
with ripening. While their study covered a much larger range of degree of ripeness, the trends are consistent with our observations over a narrower range of degrees of CX-5461 ic50 ripeness. Analysis of the headspace volatile profile using PCA showed a separation between ripe Catuai sample and the unripe and half-ripe ones ( Fig. 5c), but no separation based on the degree of ripeness was seen for the Tipica samples ( Fig. 5d). Based on the loadings, the separation between the ripe Navitoclax in vivo samples was caused by an increase in hexanal, pentanoic acid and hexanoic acid, and a decrease in furfural signals. HS volatile profiling of whole green coffee
beans is a quick and simple method and was successfully applied for the detection of defective beans (Toci and Farah, 2008 and Toci and Farah, 2014), however in our work, this approach did not prove to be robust enough to distinguish between the degrees of ripeness. Further studies into the optimisation of SPME parameters are needed to improve reproducibility and
check for the usefulness of the method for this application. This study has focused on the possibility of finding differences between green coffee beans that were harvested at different degrees of ripeness. A set of chromatographic methods was developed and optimised to analyse methanol and water green coffee extracts and to measure the headspace composition above whole green coffee beans. Differences between both coffee varieties were larger than those between the different degrees of ripeness. The best separation between the degrees of ripeness was obtained using RP-HPLC and very good differentiation between samples was achieved using PCA. The separation between the different degrees of ripeness can be attributed to an increase in 3-CQA and a decrease in much 5-CQA and di-CQAs. The total area of the HMW fraction at 280 nm in the HPSEC analysis showed clear differences between both the degrees of ripeness and the two coffee varieties. In addition, by analysing the composition of the headspace above green coffee beans, clear differences between both varieties were observed, but only the ripe Catuai sample could be differentiated in terms of ripeness using PCA. Hence, this study indicates that non-volatiles are more suited to differentiate between different degrees of ripeness of green coffee beans, while headspace profiles are more appropriate for determining differences between the two varieties examined.