Use of natural colorants in food gels. Influence of composition of gels on their colour and study of their stability during storage

Colour measurement was studied in gels prepared with four natural colorants (Annatto, Chlorophyllins, Cochineal and Curcumin), using gelatine or a mixture of xanthan gum and locust bean gum as gelling agent. A good correlation was found between sensory and instrumental evaluation, with the L∗ and H∗ parameters providing a good representation of the lightness and hue of the gels. Mathematical equations were developed, relating those parameters to the sugar and colorant concentrations. In all the gels it was found that L∗ and H∗ depended almost exclusively on the colorant concentration. The stability of the gelatine gels was studied during storage and was compared with that of commercial jellies. It was concluded that the natural colorants used (cochineal and curcumin) can replace the artificial ones found in commercial jellies.