Anthocyanins and chlorogenic acid copigmentation - influence on the colour of strawberry and chokeberry juices

The effect of copigmentation of chlorogenic acid with anthocyanins in strawberry and chokeberry juices was investigated. It was found that chlorogenic acid, at concentrations greater than that of anthocyanins, enhanced the colour intensity of these juices. The maximum copigmentation effect in both juices was observed at pH 3.4. In the investigated range of the copigment/pigment ratio, i.e. 11 to 501, absorbance increased (A) linearly with copigment content, A/g chlorogenic acid was greater in chokeberry than in strawberry juices. In solutions of purified pigments of these fruits, smaller copigmentation effects were observed than in juices under the same conditions, which indicates the participation of natural copigments present in fruits in the copigmentation process.