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Updated: Apr 18, 2026

Free Radicals in Chemical Biology: from Chemical Behavior to Biomarker Development
Published on: April 15, 2013
FT-IR spectroscopy, a reliable method for routine analysis of the degree of methylesterification of pectin in
Clare Kyomugasho1, Stefanie Christiaens1, Avi Shpigelman1
1Laboratory of Food Technology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Department of Microbial and Molecular Systems (M(2)S), KU Leuven, Kasteelpark Arenberg 22, Box 2457, 3001 Leuven, Belgium.
Abstract:
The use of Fourier transform infrared (FT-IR) spectroscopy as a method for routine analysis of the degree of methylesterification (DM) of pectin was validated. The relationship between the ratio of the intensity of the peak at around 1740cm(-1) (due to ester carbonyl group stretching) to the sum of the intensities of the peaks at around 1740 and 1630-1600cm(-1) (due to carboxylate group stretching) and the DM of pectin in model and real systems was investigated. In model systems of low to medium DM with low added protein (⩽20%), accurate DM determinations were obtained without spectra deconvolution whilst for medium to high DM pectin with high added protein (⩾30%), peak deconvolution was vital. In real systems, good DM determinations were obtained without peak deconvolution except for broccoli-derived samples. Considering that broccoli is a protein-rich vegetable, better determinations of the DM were obtained using deconvoluted FT-IR spectra.
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