Reduction of 4-methylimidazole in caramel coloring by gamma-irradiation

Abstract

4-Methylimidazole (4-MEI) is a simple nitrogen-containing heterocyclic compound, and recently classified as group 2B by International Agency for Research on Cancer (IARC). Caramel coloring is widely applied food coloring in many food products including coffee, carbonated beverages, beer and wine. In present study, y-irradiation was applied to Caramel Color III to reduce the level of 4-MEI without color changes. Caramel coloring III was y-irradiated with 1, 3, 5, 10, 30, 50 and 100 kGy. Non-irradiated caramel coloring was served as a control. The level of 4-MEI and color were analyzed on all caramel coloring. The concentration of 4-MEI in the non-irradiated caramel coloring was 714.9 mg/kg. The level of 4-MEI in caramel coloring was significantly reduced from 3 kGy y-irradiated caramel coloring (p<0.05). After 100 kGy irradiation, the amount of 4-MEI in caramel color was at 658 mg/kg, which equates 7.9% reduction from non-irradiated sample. No color change was observed on irradiated and non-irradiated caramel coloring (p>0.05). Therefore, y-irradiation could be used as an alternative processing method to improve the quality of caramel coloring by reducing 4-MEI content without its color change.