Juice sample stored under dark conditions had a better
betacyanin content compared to storage under light conditions
(Fig. 3). Stability of betalain is influenced by light (UV or
visible) because it excites the π electron of betalain chromo-
phores to a higher energy state (π*), resulting in lower acti-
vation energy and thus higher reactivity of the molecule
(Attoe and von Elbe 1981; Jackman and Smith 1996). Unlike
juice samples, betacyanin content of concentrate sample was
not significant different (p>0.05) between storage under light
or dark (Fig. 3). Attoe and von Elbe (1981) reported that as
pigment concentration increased, the influence of light on the
degradation of betanin was negligible. This could possibly
explain the negligible effect of light on the degradation of
betacyanin in the concentrated sample. This postulation, how-
ever, needs to be confirmed by further studies.
The current study shows that ascorbic acid appeared to
have a stabilizing effect on illuminated concentrate samples
as significantly higher betacyanin content (p≤0.05) was noted
(Fig. 3). Similar effect has been reported in several previous