STUDY OF THE PERICARP OF HABANERO CHILI PEPPER (Capsicum chinense Jacq.) BY RAMAN SPECTROSCOPY

Abstract

This work presents the experimental results of the study of the pericarp of unripe and ripe fruits of different varieties of habanero chili peppers (Capsicum chinense Jacq.) - Mayan Kisin, Mayan Ek and Mayan Kìin - using Raman spectroscopy. The unripe fruits of the three varieties were green, but they turned different colors at maturity: yellow (Mayan Kìin), orange (Mayan Ek) and red (Mayan Kisin). The Raman spectrum of the unripe fruit showed the presence of chlorophyll a and bacteriochlorophyll a, which are responsible for the green color observed during the immature stage. Raman spectra of ripe fruits revealed the presence of three widely dominant peaks at 1520, 1154 and 1006 cm-1 associated with the vibrations modes of the bonds C=C, C-C and C-CH3 (?1, ?2 and ?4, respectively) of carotenoids, which are primarily responsible for the color of fruits. In addition, it is also possible to see the harmonic peaks 2?1, 2?2 and 2?4, and the combinations ?1+ ?2, ?2+ ?4 and ?1+ ?4. The study of the pepper pericarp allowed identifying that the cuticle fruit originates C-H2 symmetric and asymmetric peaks at 2857 and 2908 cm1, respectively. This study suggests the Raman spectroscopic technique as a non-destructive, fast and useful tool to study the ripening process of habanero pepper.