HPLC analysis of carotenoids in orange juice

Abstract

Lutein, zeaxanthin, β-cryptoxanthin, α-carotene and β-carotene have been determined in samples of Brazilian orange juice ( Citrus sinensis). The concentrations found in factory-produced concentrates have been compared with those obtained on the Brazilian retail market and with authentic hand-squeezed juices. The analyses of the latter enabled a comparison of varieties to be made. A concentration range of 0.11–1.21 mg litre −1 was determined for total carotenoids with β-carotene, the most important source of Vitamin A, being found in the highest concentration in the Pera variety followed by Valência, Natal, Lima and Baı́a varieties. The total carotenoids present in samples of frozen concentrated orange juice (FCOJ) obtained from factories ranged from 0.26–0.48 mg litre −1, while retail samples of this product contained slightly more (0.46–0.81 mg litre −1). Frozen concentrated orange pulp-wash presented much lower concentrations, ranging from 0.04 to 0.08 mg litre −1 of total carotenoids. Fourteen samples of retail freshly-squeezed orange juice contained carotenoids ranging from 0.04 to 0.55 mg litre −1, with only one sample out of the range found for authentic samples. This could be due to the addition of pulp-wash to this sample, in which undeclared sorbic acid was also detected.