DEGRADATION RATES OF VULGAXANTHINE I

摘要

ABSTRACTThe yellow pigment, vulgaxanthine 1, was isolated and purified from yellow beets (Beta vulgaris var. lutea) to study its potential as a food colorant. Purification was accomplished by anion exchange chromatography (Sephadex DEAE), followed by adsorption chromatography on polyamide powder. Relative quantification was based on peak areas obtained by high pressure liquid chromatography (HPLC). Vulgaxanthine I was more stable at pH 5.0 than 3.0 or 7.0, and less stable in purified form than in beet juice. Half‐life values of the pigment at pH 5.0 were determined to be 27, 100, and 282 min at temperatures of 65, 55, and 45°C, respectively. The activation energy was calculated to be 25.2 ± 3.9 kcal/mole. These results show that vulgaxanthine I is quite heat labile in an oxygen‐free system and would suggest that its usefulness as a food colorant is limited to foods subjected to low temperature processing or foods subjected to a short shelf