Impact of Lignosulfonates on the Thermodynamic and Kinetic Parameters of Malvidin-3-O-glucoside in Aqueous Solutions

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Araujo, P (Author) Other; Basilio, N (Author) Other; Fernandes, A (Author) Other; Nuno Mateus (Author) FCUP; Victor de Freitas (Author) FCUP; Pina, F (Author) Other; Joana Oliveira (Author) FCUP

Journal

Title: Journal of Agricultural and Food Chemistry

Vol. 66

Pages: 6382-6387

ISSN: 0021-8561

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 13 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-00P-0FF

DOI: 10.1021/acs.jafc.8b02273

Abstract (EN): The interaction of malvidin-3-O-glucoside (1) and a lignosulfonate was studied by UV-visible spectroscopy, and the results obtained showed the formation of a complex between the negatively charged lignosulfonate and the flavylium cation form (AH(+)) of this anthocyanin at pH 1. The thermodynamic and kinetic parameters of 1 in the presence of a lignosulfonate were determined by UV-visible spectroscopy and stopped-flow techniques. The main differences were observed in the flavylium cation (AH(+))/quinoidal base (A) equilibrium, the AH(+) form being more stabilized than A (pK(al) = 4.4 +/- 0.1) compared with 1 in the absence of the lignosulfonate (pK(al) = 3.9 +/- 0.1). Furthermore, comparing the hydration (k(h) = 0.028 s(-1)) and dehydration (K_(h) = 40 M-1 s(-1)) processes of 1 in the presence of the lignosulfonate with the processes of 1 (K-h = 0.12 s(-1) and k_(h) = 35 M-1 s(-1)) show that the hydration process is slower while the dehydration process is practically unaffected in the presence of the lignosulfonate.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6