Impact of a Water-Soluble Gallic Acid-Based Dendrimer on the Color-Stabilizing Mechanisms of Anthocyanins

Luís Cruz, Nuno Basílio, Johan Mendoza, Nuno Mateus, Victor de Freitas, Maun H. Tawara, Juan Correa, Eduardo Fernandez-Megia

Research output: Contribution to journalArticle

5 Citations (Scopus)
2 Downloads (Pure)

Abstract

The interaction of two anthocyanins with a water-soluble polyanionic dendrimer was studied through UV/Vis, stopped-flow, and NMR spectroscopy. Cyanidin-3-glucoside (cy3glc) revealed a stronger interaction than malvidin-3-glucoside (mv3glc) at pH 1 according to their apparent association constants. A higher color increased was also obtained for cy3glc at pH 3.5 as a result of this stronger interaction. A high-frequency chemical shift of the cy3glc aromatic protons suggest the formation of ionic pairs. The interaction parameters (K≈700 m−1, n≈295) indicated the binding of approximately two anthocyanin molecules by each sulfate group. The equilibrium and rate constants of cy3glc in the presence of dendrimer showed an increased stability of the flavylium cation and a higher protection of this species from hydration (pK′a and pKh increased almost one pH unit). The tuning and color stabilization of anthocyanins by using this dendrimer allow novel applications as colorimetric sensors for food packaging.

Original languageEnglish
Pages (from-to)11696-11706
Number of pages11
JournalChemistry - A European Journal
Volume25
Issue number50
DOIs
Publication statusPublished - 6 Sep 2019

Keywords

  • anthocyanins
  • association constants
  • gallic acid-based dendrimers
  • NMR spectroscopy
  • UV/Vis spectroscopy

Fingerprint Dive into the research topics of 'Impact of a Water-Soluble Gallic Acid-Based Dendrimer on the Color-Stabilizing Mechanisms of Anthocyanins'. Together they form a unique fingerprint.

Cite this