ATR-FTIR spectroscopy to determine cell wall composition: Application on a large diversity of fruits and vegetables.

Affiliation

Department of Chemistry and Biology-DAQBI, Federal University of Technology-Paraná, Francisco Beltrão, Brazil. Electronic address: [Email]

Abstract

Infrared spectroscopy coupled with multivariate analyses such as linear regressions was applied to assess the main cell wall components of a huge diversity of fruits and vegetables belonging to 29 plant species. The methodology was tested on the raw freeze-dried powders and on their corresponding AIS (Alcohol Insoluble Solids) dried by solvent exchanges. The most informative spectral region was 1750-1035 cm-1. Excellent predictions (determination coefficient R2 ≥ 0.9 and residual predictive deviation RPD ≥ 3.0) were obtained for AIS yields and for arabinose, total glucose, non-cellulosic glucose, total neutral sugars, methanol and starch contents in the AIS samples. The key wavenumbers were: 1740 cm-1 for total neutral sugars; 1075, 1440-1450, 1616 and 1740 cm-1 for pectins; 895, 1035-1041 and 1160-1163 cm-1 for cellulose and 1035-1041 cm-1 for lignin. Limitations of the reference methods to analyze cell wall components (biochemical assays, spectrophotometry, chromatography) affecting the prediction accuracy were also discussed.

Keywords

Alcohol insoluble solids,Attenuated Total Reflectance Fourier Transform Infrared,Cellulose,Partial Least Square Regression,Pectins,

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