Carotenoids in Carrot

Abstract

The mature roots of most commercial varieties of Daucus carota (commonly known as carrots) accumulate massive amounts of carotenoids, a class of plastidial isoprenoid pigments that represent an essential source of retinoids (including vitamin A) and provide additional health benefits in the human diet. In plants, carotenoids participate in light harvesting and are essential for photoprotection in photosynthetic tissues, whereas their properties as natural pigments in the yellow to red range are exploited by the flowers and fruits of many plant species to attract animals for pollination and dispersal of seeds. The production of high carotenoid levels in the carrot root is a unique feature since this is an organ almost devoid of carotenoids in the vast majority of plants. In fact, carrot root was likely white before domestication and breeding generated the currently known carotenoid-rich varieties. Orange carrots are one of the richest dietary sources of provitamin A carotenoids (β-carotene and, to a lower extent, α-carotene), whereas red carrots provide a substantial amount of lycopene and yellow carrots accumulate lutein. Our knowledge of the mechanisms involved in carotenoid biosynthesis and accumulation in this vegetable has remained scarce until recently. Here, we review recent advances in this field.