Résumé
RATIONALE - Arabusta coffee was created by crossing Coffea arabica L. and C. canephora Pierre ex-Froehner after doubling the chromosome number of C. canephora. For breeding studies and coffee quality improvement, clones have been planted in French Guiana. As green bean metabolite content largely influences the coffee cup quality, biochemical and sensory analyses of Robusta and Arabusta were done on green beans and compared as part of Breedcafs H2020 project. METHODS - Arabusta cherries were harvested on 6 clones in 4 farms in Apatou and in Combi research station, and those from Robusta in Combi research station. They were wet processed before grinding. Phenolic compounds and alkaloids were quantified by HPLC (Campa et al, 2017), sucrose by enzymatic analysis (Megazyme kit, Ireland), diterpenes by NMR (Portaluri et al, 2020) and VOC by headspace SPME-GC/ MS (Marie et al, 2020). Lipids were extracted (Folch et al, 1957) and quantified by cgfb (Bordeaux). Sensory analyses followed the protocol guidelines of the Specialty Coffee Association (SCA) for C. arabica (Marie et al, 2020).We used Statistica software for analyses. RESULTS - Compared to Robusta, Arabusta had a lower caffeine content and higher trigonelline, sucrose and fatty acid contents. Arabusta evidenced both 16-O-methylcafestol and kahweol, known markers for Robusta and Arabica species, respectively. 17 of the 25 non-volatile and 23 of the 47 volatile compounds showed significant differences (p≤0.05) between Arabusta and Robusta. Except 5-caffeoylquinate and coumaroylquinate, chlorogenic acids accumulated more in Robusta. A PCA based on volatile compound content separated samples in three groups: Robusta samples, most of the Arabusta from Apatou (richer in pyrazine, toluene, 2-propanone) and those from Combi associated with 3 from Apatou (richer in D-limonene, DMSO, methyl-butanoic acid, and IBMP). A sensory analysis based on 9 sensory parameters indicated that 3 samples received a final score higher than 80. A PCA confirmed that 2 Arabusta samples were particularly different from all the others. CONCLUSIONS & PERSPECTIVES - With higher contents in sucrose, trigonelline, diterpenes, fatty acids and D-limonene and a lower content in caffeine, the composition of the Arabusta green beans seems significantly different from Robusta. The sensory analysis supports the hypothesis that some Arabusta clones possess the potential to produce quality coffee. However, it is necessary to continue the research to confirm these results. This research was funded by BREEDCAFS project, supported by the European Commission under the Horizon 2020 – Research and Innovative Program, H2020-SFS-2016-2, grant agreement number: 727934.