title: Exploring high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for metabonomic analysis of apples.
abstract: Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of (1)H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue  is presented probing its potential for metabonomic studies. The (1)H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice  preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means  of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.
authors.affiliation: University of Bern Department of Chemistry & Biochemistry, Freiestrasse 3, CH-3012 Bern, Switzerland. martina.vermathen@ioc.unibe.ch
authors.forename: Martina
authors.initials: M
authors.lastname: Vermathen
authors.forename: Mattia
authors.initials: M
authors.lastname: Marzorati
authors.forename: Peter
authors.initials: P
authors.lastname: Vermathen
mesh_terms: D027845:Malus / Q000737:chemistry*; D055432:Metabolomics / Q000379:methods*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D025341:Principal Component Analysis