Climatic factors directly impact the biochemical composition and the volatile organic compounds fingerprint in green Arabica coffee bean as well coffee beverage quality

This study was aimed at determining whether climatic conditions during bean development affected the chemical composition of the seed, the sensory perception of the coffee beverage and combinations of volatile compounds in green coffee. Using 16 experimental plots in Reunion Island displaying broad climatic variations, we showed that chlorogenic acids and fatty acids in the seed were controlled by the mean air temperature during seed development. By contrast, total lipid, total soluble sugar, total polysaccharide and total chlorogenic acid contents were not influenced by climate. Volatiles were extracted by solid phase micro-extraction and the volatile compounds were analysed by GC-MS. The results revealed that, among the climatic factors, the mean air temperature during seed development greatly influenced the sensory profile. Positive quality attributes such as acidity, the fruity character and flavour quality were correlated and typical of coffees produced at cool climates. Two alcohols (butan-1,3 diol and butan-2,3 diol) were closely correlated with a reduction in aromatic quality, acidity and an increase in earthy and green flavours. We assumed that high temperatures induce accumulation of these compounds in green coffee, and would be detected as off-flavours, even after roasting. Climate change, which generally involves a substantial increase in average temperatures in mountainous tropical regions, could be expected to have a negative impact on coffee quality. (Résumé d'auteur