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FT-IR spectroscopy, a reliable method for routine analysis of the degree of methylesterification of pectin in different fruit- and vegetable-based matrices

2014; Elsevier BV; Volume: 176; Linguagem: Inglês

10.1016/j.foodchem.2014.12.033

1873-7072

Clare Kyomugasho, Stefanie Christiaens, Avi Shpigelman, Ann Van Loey, Marc Hendrickx,

Food composition and properties

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 1740 cm−1 (due to ester carbonyl group stretching) to the sum of the intensities of the peaks at around 1740 and 1630–1600 cm−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.