Analytica (Apr 2024)

A Metabolomics Study by <sup>1</sup>H HRMAS NMR: From Sheep Milk to a Pressed-Curd Cheese: A Proof of Concept

  • David Castejón,
  • José Segura,
  • Karen Paola Cruz-Díaz,
  • Víctor Remiro,
  • María Encarnación Fernández-Valle,
  • María Dolores Romero de Ávila,
  • Palmira Villa,
  • María Isabel Cambero

DOI
https://doi.org/10.3390/analytica5020011
Journal volume & issue
Vol. 5, no. 2
pp. 170 – 186

Abstract

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For the first time, High-Resolution Magic Angle Nuclear Magnetic Resonance spectroscopy (NMR-HRMAS) was applied to directly identify specific metabolites from a Spanish raw ewe’s milk and enzymatic coagulation pressed-curd cheese (Protected Geographical Indication: Castellano) manufactured by two procedures (traditional/artisanal vs. industrial) and including the ewe’s raw milk. The NMR parameters were optimized to study the complex matrixes of this type of cheese. In addition, conventional overcrowded 1H-NMR-HRMAS spectra were selectively simplified by a Carr–Purcell–Meiboom–Gill (CPMG) sequence or a stimulated echo pulse sequence by bipolar gradients (DIFF), thus modulating spin–spin relaxation times and diffusion of molecular components, respectively. 1H-NMR-HRMAS spectroscopy displayed important information about cheese metabolites, which can be associated with different manufacturing processes (industrial vs. traditional) and ripening times (from 2 to 90 days). These results support that this spectroscopy is a useful technique to monitor the ripening process, from raw milk to commercial ripened cheese, using a minimum intact sample, implying the absence of time-consuming sample pretreatments.

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