Red beetroot owes its colour to betanin pigments. Besides
colouring, betanins also has antioxidant activity (Pitalua et al.
2010
) which has been associated with numerous health
benefits. They retain their tinctorial strength and colour shade
between pH 3 and 7 which enables its use in low-acid food.
Factors such as pH, temperature (Saguy
1979
), oxygen, light,
metal ions (Herbach et al.
2004a
) and decolourizing enzymes
(Shih and Wiley
1981
) affect the stability of betanins.
Organic acids like citric acid and ascorbic acid protect
pigment retention during processing due to its oxygen
scavenging ability (Pasch and Von Elbe
1979
). Attoe and
Von Elbe (
1981
)reportedaninverserelationshipbetween
betalain stability and light intensity explaining that visible
light absorption excites electrons of the pigment chromophore
to more energetic state. This would cause a higher reactivity
or lower activation energy for the molecule, and consequently
greater loss of the pigment