A theoretical interpretation of the color of two classes of pyranoanthocyanins

作者：Carvalho Alexandre R F; Oliveira Joana; de Freitas Victor; Mateus Nuno; Melo Andre^*

来源：Journal of Molecular Structure (Theochem), 2010, 948(1-3): 61-64.

DOI：10.1016/j.theochem.2010.02.020

• Portisins
• Vitisins
• Anthocyanins
• UV/Vis spectrum
• Red wine
• Color

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.

• 出版日期2010-5-30