Abstract
<title>Abstract</title> <p> Solid-state Nuclear Magnetic Resonance (SS NMR) spectroscopy revealed considerable chemical changes in Bengkulu Robusta coffee roasting. The <sup>1</sup> H MAS NMR spectra showed increased caffeine peak strength at 3.2 ppm after roasting, indicating higher caffeine content. Aliphatic chains were observed in the region of 1.4–1.8 ppm, and the 2D HETCOR approach confirmed correlations between proton and carbon signals at 1.8 ppm–30.58 ppm and 1.5 ppm–30.15 ppm, respectively. Melanoidins, which give the coffee a brown color, were found at 4.5 ppm. The <sup>13</sup> C MAS NMR spectra showed kahweol at 77 ppm, a chemical found in Arabica coffee, suggesting a Robusta-Arabica blend. The presence of succinate and carboxylic acid peaks at 60.3 ppm and 171.7 ppm indicated Maillard reaction products. These findings demonstrate solid-state NMR's fast and non-destructive ability to characterize roasting-induced chemical alterations. The study shows coffee producers and customers how roasting conditions affect coffee quality and authenticity. </p>