Lightness and gloss of peach gels: effect of fruit and sugar content

 Lightness and gloss were studied in peach gels prepared with different quantities of sugar and peach pulp, using a mixture of xanthan and locust bean gum as gelling agents. Colour was described in terms of the colour coordinates established by the Commission Internationale de l'Eclairage and gloss was determined as a percentage. The values of lightness determined optically (L^*), when ranked, corresponded well with those determined by eye, but there was less similarity between the ranked values of gloss determined optically and by eye. There was a clear relationship between the sensory evaluation of lightness and gloss and the fruit and sugar content of these gels. Mathematical equations were developed to relate both L^* and gloss values determined optically with fruit and sugar concentrations. It was found that fruit had a greater effect than sugar on the L^* values and that gloss depended only on the sugar content. Finally, the gloss of gels prepared with different gelling agents were compared and it was found that lightness can affect the sensory evaluation of gloss. Received: 15 July 1997 / Revised version: 3 February 1998