FT-IR, FT-Raman spectroscopic study of carotenoids from saffron (Crocus sativus L.) and some derivatives

The carotenoids of saffron, crocins (CRCs), were extracted and their derivatives, dimethylcrocetin (DMCRT) and crocetin (CRT) were prepared from the extract by alkaline hydrolysis in methanol (DMCRT) and by alkaline hydrolysis in water followed by acidification (CRT), respectively. FT-IR, FT-Raman spectroscopies were used to study these compounds. The FT-IR spectra of CRCs, DMCRT and CRT have characteristic absorbance bands between 1706 and 1664 cm−1 (νCO) and in the region between 1243 and 1228 cm−1 (νC–O). Two main Raman lines were observed near 1540 and 1166 cm−1 which are respectively assigned to (νCC) and (νC–C) stretching modes.