Carotene Reactivity in Pink Grapefruit Juice Elucidated from Model Systems and Multiresponse Modeling

This study was carried out to assess the impact of pink grapefruit juice composition and structure on the degradation kinetics of lycopene and beta-carotene using model systems and multiresponse modeling. Carotenes were heated at four temperatures in their native matrix (juice) or were extracted and incorporated in water/ethanol emulsion systems forrimlated with or without ascorbic acid or naringin. Kinetic analysis showed that the rate constants and activation energy were lower for lycopene than for beta-carotene in the juice, while this trend was inversed in the model system. Multiresponse modeling was used to analyze the role of ascorbic acid and naringin in carotene degradation. Ascorbic acid had a very low impact, while naringin significantly increased the carotene degradation and isomerization rates. We concluded, that lycopene was more sensitive to thermal degradation and phytochemical interactions than beta-carotene, but this behavior was masked in the fruit juice matrix by better structural protection.