Jambolan anthocyanins showed lower colour intensity when
compared to anthocyanins of red sweet potato, purple corn, purple
carrot, red grape (Cevallos-Casals & Cisneros-Zevallos, 2004) and
red cabbage (data not shown). It is due to glycosylation structure
of jambolan anthocyanins as 3,5-diglucoside. Mazza and Brouillard
(1990) reported that malvidin 3,5-diglucoside (malvin) and cyanidin
3,5-diglucoside (cyanin) cannot confer much colour to a solution
whose pH ranges from 3 to neutrality because of the high
value of the equilibrium constant of the hydration reaction (Kh).
The anthocyanin monoglucosides are known to possess Kh constants
about 10 times smaller than the corresponding diglucosides.