Cross-linking of sodium carbonate-soluble pectins from apple by zinc ions

Diana Gawkowska; Justyna Cybulska; Artur Zdunek

doi:10.1016/j.carbpol.2018.05.024

Cross-linking of sodium carbonate-soluble pectins from apple by zinc ions

Carbohydr Polym. 2018 Sep 15:196:1-7. doi: 10.1016/j.carbpol.2018.05.024. Epub 2018 May 8.

Authors

Diana Gawkowska¹, Justyna Cybulska², Artur Zdunek³

Affiliations

¹ Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland. Electronic address: d.ganczarenko@ipan.lublin.pl.
² Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland. Electronic address: j.cybulska@ipan.lublin.pl.
³ Institute of Agrophysics, Polish Academy of Sciences, Doświadczalna 4, 20-290 Lublin, Poland. Electronic address: a.zdunek@ipan.lublin.pl.

PMID: 29891275
DOI: 10.1016/j.carbpol.2018.05.024

Abstract

Sodium carbonate-soluble pectin fraction forms a self-organized network on mica and may have the potential ability to bind zinc ions. The aim of this research was to characterize the interaction of zinc ions with this fraction extracted from apples using rheological measurements and FT-IR study. The addition of zinc ions (10 and 20 mM of ZnSO₄·7H₂O) to 5% pectin water solution caused a significant increase in viscosity, which may be connected with the formation of a pectin network. Moreover, the addition of zinc ions resulted in an almost 1.5-fold decrease in the flow behaviour index and a 5-fold increase in the consistency index. FT-IR studies showed a decrease in the intensity of the bands connected with ν_as and ν_s(COO^-) and γ(COH)_ring as a result of the presence of zinc ions. Therefore, it may be supposed that these ions interact with the carboxylate and hydroxyl groups of galacturonic acid units.

Keywords: FT-IR spectroscopy; Pectin; Principal component analysis; Rheology; “Egg-box” model.