beetroot
eggplant
While it is botanically a fruit, an Aubergine is considered to be a culinary vegetable, it is purple and begins with 'A'.
Saffron is called Vegetable Gold. It is actually a purple flower.
vegetable dye
a purple food is a fruit vegetable flower candy etc. etc. etc.
· eggplant · endive
grape
There are a number of varieties of purple potatoes.
Broccoli
Eggplant is a dark purple or brownish-purple color that resembles the color of the outer skin of European eggplants. Another name for the color eggplant is aubergine
'Saffron ' obtained from the stigma of crocus sativus which is a showy purple coloured flower is also known as vegetable gold.
vegetable butter