Influence of rootstock and cultivar on bioactive compounds in citrus peels.

Background: Citrus fruits have a beneficial effect on human health because of their nutritional and antioxidant properties, and their consumption is associated with a decrease in the incidence of cardiovascular disease and reduced risk of certain cancers. Seven cultivars of mandarin and orange species from the Mediterranean area, grafted onto different rootstocks (Cleopatra mandarin and Troyer citrange), have been analysed. The influence of the rootstock on the content of bioactive compounds is discussed.

Results: In all citrus cultivars and rootstocks studied, hesperidin and narirutin flavonoids were the main flavanone glycosides identified, β-cryptoxanthin and violaxanthin the most abundant carotenoids, limonene was the most abundant essential oil, calcium and potassium were the dominant macronutrients and, among the micronutrients, iron and boron represented the highest proportions.

Conclusion: We have been found clear differences in the content of bioactive compounds for the different groups, in agreement with the Citrus classification. Although both mandarin and orange varieties showed similar tendencies concerning the majority of bioactive constituents, the proportion of the individual nutrients ranged among different cultivars and our results indicated differences between rootstocks although it would be necessary to carry out more analyses, and with the new rootstocks obtained from different breeding programmes, to elucidate conclusive values.