Raman analysis of caraway (Carum carvi L.) single fruits. Evaluation of essential oil content and its composition.

FT-Raman spectroscopy was applied for in situ analysis of single and intact fruits obtained from a diverse caraway (Carum carvi L.) collection. The Raman spectra showed characteristic bands that could be assigned to lignin, unsaturated fatty acids, and polysaccharides. Additionally, the essential oil composition was determined by gas chromatography (GC), which showed a great variation in carvone and limonene content among accessions obtained from European botanical gardens as well as advanced breeding materials. GC data and information obtained from Raman measurements were correlated and allowed development of calibration models for essential oil yield and carvone and limonene content (R(2) = 74%, 81%, and 75%, respectively). The congruence between results obtained by both techniques indicates FT-Raman spectroscopy to be a valuable screening tool for quality control and selection of fruits with desired essential oil composition, which can be performed without fruit destruction.