Tomato plants contain a variety of flavonoids in their
vegetative tissues, including anthocyanins [14]. In the
fruit, they accumulate only small amounts of naringenin
chalcone (a flavonoid biosynthetic pathway intermediate)
and some flavonols, such as quercetin and kaempferol
glycosides, which are concentrated in the peel but do not
synthesize anthocyanins [2,14]. ‘Black’ or ‘purple’ fruits
often described in some heirloom varieties result from
mutations affecting chlorophyll breakdown and carotenoid
content but are not related to anthocyanin production [14].
By contrast, the production of anthocyanins in the fruit is