Pigments present in vegetables include the water insoluble plastid pigments , the chlorophyll and carotenoids and the cell-sap soluble pigments- the anthocyanins, flavones , flavonols, and similar substances. These pigments may change in colour as a result of a change in physical state or of chemical reaction with metals, metallic salts, acids, alkalis, oxygen,etc.
The bright colours of many vegetables contribute much to their appeal. The colours result from the various pigments contained in their tissues. The chief pigments of vegetables and fruits can be classified as water insoluble and water soluble.