Photodegradation of Carotenoids in a Vegetable Juice System

The kinetics of carotenoid photodegradation in a vegetable juice system were studied by exposing samples in glass vials to 230 ft‐c of light at 4°C. Carotenoids were analyzed using HPLC at selected times during an 8‐day period. Color changes were monitored using a Gardner colorimeter. Degradation reactions fit a first‐order kinetic model. Lycopene degradation was about one‐fifth that of α‐carotene and β‐carotene with rate constants of 0.061. 0.273 and 0.309 day −1 . respectively. Colorimeter results showed a significant decrease in “yellowness” that correlated with the loss of α‐ and β‐carotene (r 2 = 0.97).