Development of caramel colour with improved colour stability and reduced 4-methylimidazole

Abstract

This study investigated the effect of chemical substances, such as Mg2+ (as magnesium sulphate), Zn2+ (as zinc sulphate), Fe2+ (as iron sulphate), ascorbic acid, and citric acid, on the formation of 4-methylimidazole (4-MI) and colour stability of caramel colour. The 4-MI concentration in the caramel colour without chemical substances was 963.10 mu g/g, and this decreased the most (67.7%) with the addition of 0.1 molar ratio of citric acid. Colour stability was evaluated by measuring the total colour change (Delta E) after storage, and heating in pH 2, 4, and 7 solutions and 50% solution in ethyl alcohol. Among the chemical substances added to reduce 4-MI in the caramel colour, Mg2+ (0.1 molar ratio) and ascorbic acid improved the colour stability more than the others.