pH-regulated interaction modes between cyanidin-3-glucoside and phenylboronic acid-modified alginate

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Luis Cruz (Author) FCUP; Nuno Mateus (Author) FCUP; Victor de Freitas (Author) FCUP

Journal

Title: Carbohydrate Polymers

Vol. 280

ISSN: 0144-8617

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 9 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-00V-YH0

DOI: 10.1016/j.carbpol.2021.119029

Abstract (EN): Stabilizing mechanisms through covalent and non-covalent interactions have been studied along the years for color stabilization of anthocyanin dyes. In this work, the chemical functionalization of a natural and biocompatible marine-based polysaccharide (alginic acid) with 3-aminophenylboronic acid via carbodiimide coupling chemistry was carried out in order to create a bifunctional material for pH-dependent selective interaction with colored cyanidin-3-glucoside chemical species. The interaction studies were performed by UV-Vis, H-1, and B-11 NMR spectroscopy. Overall, the apparent acidic and hydration constants are more stabilized in the presence of phenylboronic acid-modified alginate. For more acidic pH values the red cationic flavylium cation of cyanidin-3-glucoside mainly interacts through non-covalent electrostatic interactions with the carboxylate groups of the biopolymer derivative with association constant around 0.5 mM(-1) while at higher pH values boronate-catechol covalent bonds are favored, promoting the stabilization of the colored neutral and anionic quinoidal bases of anthocyanins instead of colorless hemiketal and chalcones.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9