Biochemical Composition of the Beans of Local Coffee Cultivars from Southwestern Saudi Arabia

Coffee (Coffea arabica L.) is an economically and culturally important crop for the communities of the southwest mountain regions of Saudi Arabia. The objective of the study was to characterize the biochemical composition of the dry green beans of the coffee cultivars grown there. The analysis of variance revealed significant differences among the 66 accessions studied for all eight biochemical compounds analyzed especially, caffeine, trigonelline and chlorogenic acid. Remarkably, caffeine concentrations varied from 0.75 g 100 g-1 in accession KSA38-1.51 g 100 g-1 in KSA-47 and trigonelline concentrations varied from 0.81 g 100 g-1 in KSA-69-1.64 g 100 g-1 in KSA-6R. However, 55% and 64% of the accessions had low to moderate caffeine and trigonelline concentrations, respectively. Chlorogenic acid concentration varied from 2.35 g 100 g-1 in KSA-3R to 4.33 g 100 g-1 in KSA-32. Because these compounds are the most important bitterness attributes contributing to coffee quality, significant differences in beverage quality are expected between the accessions. Furthermore, the results of the multivariate analysis indicated the presence of considerable diversity among the 66 accessions. The hierarchical cluster analysis grouped the genotypes into fourteen clusters. The observed divergence suggests that genetic gains for biochemical features are possible. Therefore, we recommend accessions KSA-1, KSA-9R, KSA10, KSA-29, KSA34, KSA37, KSA-38, KSA-39 and KSA-60 for further evaluation.