Flavor evaluation using taste sensor for UHT processed milk stored in cartons having different light permeabilities

In order to investigate the influence of light exposure on the flavor of milk, UHT processed milk contained in gable-top cartons of five different colors (white, red, blue, green, and black), which were stored under fluorescent light at 10°C for 10 days, were evaluated by several methods. The results of the sensory evaluation confirmed that the black carton was most effective in preventing off-flavor due to light and that the milk in the white carton had the highest off-flavor. Furthermore, no difference was found in the flavor of the milk in the red, blue, and green cartons. GC/MS analysis of volatile compounds in each milk showed that the amount of hexanal was the highest in the white carton and the lowest in the black carton. The amounts of hexanal in the red, blue, and green cartons were intermediate between those in the white and black cartons. Taste sensor analysis found a correlation between sensor response values and sensory evaluation scores or hexanal amounts. Thus, it was suggested that hexanal is effective as an indicator of off-flavor and that the taste sensor analysis was as effective as sensory evaluation as a means of objectively evaluating off-flavor.