The black carrot: rediscovering an ancient vegetable from a nutraceutical point of view

Long before the orange carrot became established in the 16th century, the black carrot (Daucus carota ssp. sativus var. atrorubens) existed across Asia and eastern Mediterranean. The black carrot is still grown and consumed in oriental countries such as Turkey, Egypt and India. It shows an attractive bluish-purple colour conferred by the high anthocyanins levels and its extracts can serve as a natural food dye, because of their high heat, light and pH stability. Today black carrot extracts are used in juices, confectionery and soft drinks, as a healthy alternative to synthetic dyes. In recent years, several studies have shown that phenolic compounds and anthocyanins display a wide range of biological activities, including antioxidant, anti-inflammatory and anti-carcinogenic activities. They display also a variety of effects on blood vessels, platelets and lipoproteins, able to reduce the risk of coronary heart diseases. For these reasons, a complete evaluation of the content of these compounds is critical to understand the nutraceutical power of this ancient vegetable. The aim of this research is the development and validation of an analytical method based on HPLC-F for the content control in black carrots of several classes of bioactive compounds such as aminoacids, phytohormones and organic acids. Spectrofluorimetric detection, taking advantage of the natural fluorescence of these analytes, ensures high method selectivity and sensitivity, while maintaining a good feasibility as there is no need for time- and money-consuming derivatisation procedures. The developed method is going to be applied for the analysis of black carrots coming from the Italian market and of commercial products containing their extracts.