The Raman spectrum of CBP is shown in Fig. 4. It can be observed
that the spectra of the pigment from C. burmannii' peel mainly
comprise two bands at 1583 and 1341 cm−1 that are very similar to
the Raman patterns observed natural pigment isolated from Sepia
officinalis (Centeno & Shamir, 2008). This can be interpreted as
originating from the in-plane stretching of the aromatic rings and the
linear stretching of the C–C bonds within the rings, along with some
contributions from the C–H vibrations in the methyl and methylene
groups (Huang et al., 2004).