Raman spectroscopy and chemometrics to analyze bright orange floral heads from native Mexican Tagetes erecta

This study presents a Raman spectroscopy analysis combined with chemometrics methodologies, using principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models to demonstrate the utility of this spectroscopic technique as a monitoring tool for detecting carotenoids in flower heads of Tagetes erecta (marigold known as cempasuchil), a symbol of the cultural heritage of Mexico. The research focuses on orange flower heads collected from various locations in the state of Guerrero, Mexico; the acquisition of Raman spectra of ligule tissue of flower heads using a 532 nm laser, and the identification and integration of five characteristic vibrational bands of the carotenoids, followed by multivariate analysis to distinguish possible groupings and samples with distinctive characteristics. The results highlight the potential of Raman spectroscopy combined with PLS-DA to detect and monitor the presence of carotenoids in genetic improvement studies.