Table 1
Stability of indicaxanthin and betanin dyes during heating at 90 ◦C.
Absorbance at 475 nm
(indicaxanthin)
Absorbance at
538 nm (betanin)
t = 0 min 0.443 0.140
t = 120 min 0.381 0.014
Thermal degradation (%) 14 90
The average amount obtained for the indicaxanthin after column
chromatography was about 75 mg per 50 g of juice and for
the betanin was about 5 mg per 50 g of juice with a ratio of about
15:1. The identity of indicaxanthin was determined by retention
time (Fernando et al., 2010) and confirmed by the usual analytical
methods. In particular, electrospray mass spectrometry in the positive
ionisation mode, showed a molecular ion (m/z 309, [M+H]+,
80%) (Fig. 4).