Thermodynamic investigations of the copigmentation process between strawberry anthocyanins and rose petal polyphenols (Rosa damascena Mill.) at different temperatures

Abstract

In this study the model systems between strawberry anthocyanins as pigment and rose polyphenols as copigment was investigated. The solutions were prepared from 1:2 to 1:10 pigment:copigment. The addition of increasing concentrations of rose petal polyphenols resulted in a gradual increase of hyperchromic effect. The absorption was determined at heating system from 20 to 50 oC and following cooling the same system from 50 to 20 oC. All calculated thermodynamic parameters were negative. The copigmentation reaction was determined as spontaneous, exothermic and thermally reversible.