Comparative study on the carotenoid composition of the peel and the pulp of different citrus species

The carotenoid compositions of the peel and the pulp of various citrus fruits were compared with HPLC methods using C18 and C30 columns. The extracts usually contain β-cryptoxanthin and lutein in considerable amounts and in all species except lime, the red apocarotenoid β-citraurin as well. In case of lime and mandarin the carotenoid compositions of peel and pulp show a good coincidence while in orange, clementine, grapefruit, lemon and kumquat there are a lot more differences. Lime extracts contain practically only two carotenoids: β-carotene and lutein. The carotenoid components of the saponified extracts of kumquat were separated on calcium carbonate columns and were investigated in detail. The components were identified with HPLC–DAD and HPLC–MS.Industrial relevanceCitrus fruits are important starting materials for juice production. Their carotenoid fingerprint shows differences not only in different species but the proportion of certain pigments can be different in the same fruit according to where the plants were grown and how they were processed. Comparison of the carotenoid content of different fruit products (e.g. juices) can give us useful hints about the quality of the product and about the amount of these important natural antioxidants.