Volatile Metabolite Profiles of Robusta Green Bean Coffee From Different Geographical Origins in West Java and Their Correlation With Temperature, Rainfall, and Altitudes Using SPME GC-MS-Based Metabolomics.

Abstract

The chemical composition, including volatile metabolites of green coffee beans, is influenced by geographic origin. The aim of this study was to reveal the volatile metabolite profile of a single variety of Robusta green bean coffee from five major plantation regions in West Java and to correlate these profiles with temperature, rainfall, and altitude. By using solid phase micro extractions and gas chromatography-mass spectrometry, 143 different volatile compounds were detected, with aromatic hydrocarbon, alcohols, monoterpene, pyrazines, sesquiterpenes, carboxylic acids, and terpene the most dominant. Principal component analysis (PCA) indicated 64.3% variability, showing that the metabolite profile of Robusta green coffee from the Bogor region was distinctly different from those in Ciamis, Kuningan, Sumedang, and Tasikmalaya, which were more similar to each other. Metabolites such as benzaldehyde, isovaleric acid, toluene, diisobutyl succinate, 1-heptene, 4-dodecene, caffeine, acetic acid, and methyl benzoate were identified as key discriminants, with a VIP score greater than 1.5. Temperature increases were linked to higher levels of isovaleric acid, diisobutyl succinate, 4-dodecene, toluene, and acetic acid, while other discriminant metabolites declined. Increased rainfall was associated with higher levels of benzaldehyde, 1-heptene, caffeine, and methyl benzoate, but lower levels of the other discriminants. Altitude had a positive correlation with methyl benzoate and 1-heptene, and a negative correlation with isovaleric acid and 4-dodecene, with weaker correlations for other compounds. In summary, Robusta green coffee beans from different regions of West Java can be distinguished by their volatile metabolites. Bogor green coffee beans had higher levels of benzaldehyde, 1-heptene, caffeine, and methyl benzoate, Kuningan beans had more diisobutyl succinate and 4-dodecene, Ciamis beans had higher levels of isovaleric acid, diisobutyl succinate, and 4-dodecene, while Sumedang and Tasikmalaya beans were similar, with higher levels of isovaleric acid, diisobutyl succinate, 4-dodecene, toluene, and acetic acid. This difference is related to the climatic factors of temperature and rainfall, as well as the altitude at which Robusta coffee is grown.