RESULTS AND DISCUSSION
In the present study we have made use of anthocyanin extracted from Rose flowers and used
for acid – base titration. The intrinsic pH was 2.88. The spectroscopic data of the extracted
anthocyanin pigments indicate a shift in wavelength maxima of the colors by addition of
stannous salt and the complex not only showed change in pH of the aqueous medium but it
also showed change in λmax. The extract showed wavelength maxima change from 517 nm
(dark pink) to 592 nm (green) between the pH range 2 to 9. Significant changes were
observed when stannous salt was added to the rose anthocyanin extract. With the addition of
Stannous salt the pH falls from 2.88 to 1.72 with change in λmax to 520 nm. Similar trend was
observed at pH 6 and 9 where the change in λmax. is 560 and 582 nm respectively as shown in
table-1.