THE COLOUR AND STABILITY OF CYANIDIN AND CYANIDIN

The relationships between the color variation, colour intensity, thermal stability and brown index (BI) of the aglycone moiety of cyanidin and its 3-glucosidic substitution in cyanidin 3-O-β-glucopyranoside (Cy3Glc) were studied in the aqueous solution at pH 7.0 and under the conditions of the elevated tempera-ture (55.0±0.1 °C) which simulate the rapid food ageing. Both studied com-pounds showed a hypsochromic shift during the storage. The cyanidin showed a significantly higher colour intensity and greater thermal stability compared to Cy3Glc. The gradual loss of the colour of the Cy3Glc solution was accom-panied by the increase in BI. The BI for cyanidin was 0.63 and ˂1 while for Cy3Glc it was 1.09 and ˃1 all the time thus giving yellowish shades to the Cy3Glc aqueous solution. These facts are important from the point of view of using these compounds as food colorants, indicating a higher tinctorial power and higher stability of cyanidin compared to the Cy3Glc