abstract
The application of nuclear magnetic resonance (NMR) spectroscopy, hyphenated NMR, and diffusion-ordered spectroscopy (DOSY) to the characterization of mango juice, as an example of a complex food mixture, is described. The compositional changes taking place as a function of ripening were followed, and selected metabolites were quantified by integration of the corresponding NMR peaks. In this way, an overall view of the metabolite changes is obtained, enabling the study of the biochemical mechanisms involved in the ripening process. More than 50 compounds were identified by 1D- and 2D-NMR, but many ambiguous assignments remain due to spectral overlap or insufficient coupling information. The use of Liquid Chromatography (LC-NMR) and LC-NMR/Mass Spectrometry (MS) enables a fuller characterization of the soluble pectin fraction to be made; its dependence on ripening stage is discussed. Finally, DOSY adds information on the M(r) of many metabolites, including the pectin fractions of ripe and unripe mango juices, and enables further peak assignments to be made.
keywords
NUCLEAR-MAGNETIC-RESONANCE; HAIRY RAMIFIED REGIONS; LIQUID FOODS; IDENTIFICATION; RHAMNOGALACTURONASE; SPECTROMETRY; PECTINS; ACIDS; BEER; H-1
subject category
Spectroscopy
authors
Duarte, IF; Goodfellow, BJ; Gil, AM; Delgadillo, I
our authors
Ana Maria Pissarra Coelho Gil
Associate Professor with Aggregation
Brian James Goodfellow
Assistant Professor