Natural food and beverage colourings - Natural Food Additives, Ingredients and Flavourings - page 31

slowed by the removal of water. The range of applications for such a formulation
is limited to where the pH is non-acidic to prevent the equilibrium reaction
returning the shade to red. An alternative approach to create a blue anthocyanin is
to react the anthocyanin with a metal ion (typically aluminium) to form a lake.
The advantage of such a formulation is that it is more tolerant to pH but the
chemical reaction stage could impact on its perception of being truly natural.
The classical problems seen with anthocyanins are either with incorrect
changing of shade as pH changes and a browning reaction with ascorbic acid
(vitamin C). Anthocyanins and ascorbic acid are mutually destructive and the
result is the change from the initial red colour to a brown colour with the co-current
loss of vitamin C which could be problematic in vitamin-enriched drinks making
a content claim.
One effect that can happen with predominantly grapeskin anthocyanins is the
polymerisation of molecules as an anthocyanin extract ages. The impact is that the
colour shade becomes less blue and more brown notes are exhibited; any foam
formed in processes such as bottling becomes stabilised and also an astringent
taste can come through. Unfortunately there is little that can be done to mitigate
this problem once it has occurred.

2.2.5 Chlorophyll/chlorophyllin
Chlorophyll is the most widely occurring of all the natural pigments. 11 It is present
in all green plants, algae and some bacteria. The name is derived from the Greek
chloros meaning green and phyllon meaning leaf. Chlorophyll is required for
photosynthesis, which allows plants to obtain energy from light. Chlorophyll is
the starting point for all subsequent pigment derivatives.
Permitted sources for extraction are edible plant materials and commercially
the most signifi cant are grass and lucerne (alfalfa). Solvent extraction of dried and
ground plant material yields chlorophyll, which is naturally oil-soluble and
provides an olive green colour. Alkaline hydrolysis of chlorophyll produces
water-soluble chlorophyllin by the removal of a hydrocarbon side chain.
Chlorophyll is based on a porphyrin ring structure and at its heart is a
magnesium ion. Reaction with copper salts can cause an exchange leading to the
formation of copper chlorophyll(in). The impact on the 'naturalness' of this
pigment as it is converted from chlorophyll to copper chlorophyllin is a point of
discussion between many parties involved in the supply of colour to the food
industry with no universal or legally binding agreement.
Copper chlorophyll and copper chlorophyllin provide a much more intense,
brighter blue/green colour than the uncoppered product with greater stability to
heat and light in application. Commercial forms exist for all four possible
derivatives of chlorophyll, but the most commercially signifi cant are water-
soluble copper chlorophyllin based products (typically 10%), giving a crystal
clear colour in application.
Key applications for copper chlorophyllin are sugar confectionary, beverages,
ice cream, water ices, fruit preparations, decorations and coatings, sauces and also

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