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Variability of cork from Portuguese Quercus suber studied by solid‐state 13 C‐NMR and FTIR spectroscopies
Author(s) -
Lopes M. H.,
Barros A. S.,
Pascoal Neto C.,
Rutledge D.,
Delgadillo I.,
Gil A. M.
Publication year - 2001
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1022
Subject(s) - fourier transform infrared spectroscopy , suberin , cork , chemistry , quercus suber , analytical chemistry (journal) , chemometrics , magic angle spinning , spectroscopy , lignin , nuclear magnetic resonance spectroscopy , chromatography , stereochemistry , organic chemistry , chemical engineering , biochemistry , physics , quantum mechanics , engineering
A new approach is presented for the study of the variability of Portuguese reproduction cork using solid‐state 13 C‐NMR spectroscopy and photoacoustic (PAS) FTIR (FTIR‐PAS) spectroscopy combined with chemometrics. Cork samples were collected from 12 different geographical sites, and their 13 C‐cross‐polarization with magic angle spinning (CP/MAS) and FTIR spectra were registered. A large spectral variability among the cork samples was detected by principal component analysis and found to relate to the suberin and carbohydrate contents. This variability was independent of the sample geographical origin but significantly dependent on the cork quality, thus enabling the distinction of cork samples according to the latter property. The suberin content of the cork samples was predicted using multivariate regression models based on the 13 C‐NMR and FTIR spectra of the samples as reported previously. Finally, the relationship between the variability of the 13 C‐CP/MAS spectra with that of the FTIR‐PAS spectra was studied by outer product analysis. This type of multivariate analysis enabled a clear correlation to be established between the peaks assigned to suberin and carbohydrate in the FTIR spectrum and those appearing in the 13 C‐CP/MAS spectra. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 268–277, 2001