Chlorophyll is often used as a natural colouring agent due to its green colour. Its use in the food industries is becoming increasingly popular due recent legislation shifts which mandated the use of natural colouring agents in preference to artificial agents [51]. There are, however, disadvantages associated with use of chlorophyll as a colouring agent. Not only is chlorophyll generally more expensive than artificial colourings, but also tends to be unstable under the different pH conditions of the foods to which it is added. To resolve this instability, the chlorophyll molecule must undergo a chemical modification which replaces its magnesium centre with a copper ion before it is mixed with the food materials. Since the modified chloro­phyll cannot be metabolically absorbed and is eventually removed from the body as an excretion product, this complex is considered safe to replace the original

chlorophyll as a colouring agent in most developed countries. The concentration of free ionisable copper in the food must, however, be kept below 200 ppm under current regulations [20, 54].