The colour of fruit and vegetables

Anthocyanins. The anthocyanin pigments impart the pleasing red and purple colours associated with many fruits and vegetables. They belong to the class of compounds referred to as ‘flavonoids’ and, in chemical terms, they are flavylium salts differing in the number and position of free or methylated hydroxyl groups and with a sugar moiety linked through position 3 or positions 3 and 5 in the ring. A commonly occurring anthocyanin pigment, cyanidin‐3‐glucoside, is shown in figure 3. The anthocyanins are soluble in water and are unstable under a variety of enzymic and non‐enzymic conditions.