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 μg/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 (ΔE) 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.
Keywords: 4-Methylimidazole; caramel colour; chemical substances; colour stability; organic acid.