Effect of thermal treatment on carotenoids, flavonoids and ascorbic acid in juice of orange cv. Cara Cara

This study evaluated the impact of thermal treatment on the degradation of carotenoids, flavonoids and ascorbic acid in juice of orange cv. Cara Cara. A total of 42 carotenoids were detected in the Cara Cara juice and the simulated system, and the newly formed compounds were identified as isomers derived from β-cryptoxanthin, β-carotene, lycopene, phytoene and phytofluene. During thermal treatment, carotenes of lycopene, phytoene and phytofluene were highly stabile in Cara Cara juice probably due to the matrix protection, while they decreased by 70.85%, 12.50% and 45.59% respectively in the simulated system following the first-order degradation reaction (k = 1.70 × 10^-3, 2.90 × 10^-4 and 6.28 × 10^-4). Epoxy-carotenoid esters were sensitive to the low pH of the Cara Cara juice and esterified β-cryptoxanthin was the only ester group survived by thermal treatment. Thermal degradations of total caotenoid, flavonoid and ascorbic acid in Cara Cara juice were fitted by bi-exponential function.