A theoretical interpretation of the color of two classes of pyranoanthocyanins

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Alexandre R F Carvalho (Author) Other; Joana Oliveira (Author) FCUP; Victor de Freitas (Author) FCUP; Nuno Mateus (Author) FCUP; Andre Melo (Author) FCUP

Journal

Title: Journal of Molecular Structure: THEOCHEM

Vol. 948

Pages: 61-64

ISSN: 0166-1280

Publisher: Elsevier B.V.

Indexing

ISI Web of Knowledge - 12 Citations

Scopus - 16 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-6MW

DOI: 10.1016/j.theochem.2010.02.020

Abstract (EN): Anthocyanins are natural pigments that present a characteristic red color at low pH (<2). Anthocyanin-pyruvic acid adducts, commonly referred to as vitisins, are anthocyanin derivatives usually found in red wines. Looking at the two-dimensional structures, vitisins apparently have a greater conjugation system than anthocyanins. Following the common conjugation rules, making the chromophore more conjugated increases the value of lambda(max), and vitisins should have a longer lambda(max) than anthocyanins. However, they have a surprising lower lambda(max), presenting an orange color, under the same pH conditions. Another class of anthocyanin-derived pigments, portisins have the expected relative behaviour with a longer lambda(max) than anthocyanins. In this work, a quantum study on molecular models of pigment models was carried out. The results obtained enabled to present a putative explanation of the color change in these series.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4