Determine the parts of plant source
The natural food colourants from plant sources are classified into 5 types:
a) Anthocyanins,
b) Betalaines,
c) Carotenoids,
d) Chlorophylls and
e) Curcumin.
Literature has been well documented, with a lot of research work going into varied aspects of colourants from the above plant sources. A variety of fruits, vegetables and flowers have also been studied as potential sources of colourants. One of the novel sources has been tissue culture of grape varieties. The callus induced from the anther of grape plants is transplanted to a liquid culture medium and cultured aerobically. Pigment is then extracted from the culture which can be manipulated to give maximum colour yield during growth, by adding various chemicals to the medium or irradiating with light.