The FTIR spectra of caffeine and plain polysaccharides as carriers
for the encapsulation of caffeine, as well as the formulated
beads, are illustrated on Fig. 3a–c. In the spectrum of caffeine
(Fig. 3a) in KBr, the band at 3093 cm1 corresponds to C–H stretching
of heterocyclic compounds, while the strong bands at 1699 and
1659 cm1 are attributed to the carbonyl group of amide (amide I)
and an additional absorption band at 1539 cm1 of amide II. The
FTIR spectrum of plain alginate (A) (Fig. 3a) shows a characteristic
band of OH stretching and intra- and intermolecular hydrogen
bonds at about 3400 cm1. The spectrum also displays a strong
band at 1608 cm1 which corresponds to frequencies of a carbonyl
group of carboxylic acid. The spectra of 2% and 3% alginate (2% A
and 3% A) are very similar, and the presence of caffeine in these