NMR Identification and Quantification of Galactinol in Green Coffea arabica: Implications for Traceability and Adulteration.

Among coffee low-molecular-weight carbohydrates, galactinol plays an important role in coffee physiology and quality, having received attention also for its potential use as a marker of geographical origin. Nevertheless, data on the occurrence of this sugar in green coffee beans remain limited. In this study, galactinol was isolated for the first time from green Coffea arabica beans and unambiguously identified by high‑field NMR spectroscopy. A quantitative HPLC-RID screening of 100 green Arabica coffee samples from 16 geographical origins showed that galactinol was detected in 31% of the samples, with consistent occurrence in Ethiopian coffees but sporadic or absent detection in several other origins. Notably, the chromatographic analysis revealed a previously unreported co-elution of galactinol with ciceritol, a chickpea-derived cyclitol of relevance for coffee adulteration detection. These results highlight both the potential and the limitations of galactinol as a geographical marker and stress the importance of combining chromatographic and structure‑specific spectroscopic approaches to ensure reliable interpretation in coffee traceability and authenticity studies.