Graphical exploration of 600- and 60-MHz proton NMR spectral datasets from ground roast coffee extracts

Abstract

This article uses a variety of graphical and mathematical approaches to analyse 600- and 60-MHz ('benchtop') proton NMR spectra acquired from lipophilic and hydrophilic extracts of roasted coffee beans. The collection of 40 authenticated samples comprised various coffee species, cultivars and hybrids. The spectral datasets were analysed by a combination of metabolomics approaches, cross-correlation and whole spectrum methods, assisted by visualisation and mathematical techniques not conventionally employed to treat NMR data. A large amount of information content was shared between the 600-MHz and benchtop datasets, including in its magnitude spectral form, suggesting the potential for a lower cost, lower tech route to conducting informative metabolomics studies.

Keywords: benchtop NMR; coffee; compact NMR; graphical exploration; high‐resolution NMR; inter‐correlation; magnitude spectra; metabolomics; spectral form; visualisation.