Cardamom (Elettaria cardamomum) is the third most expensive spice in the world. “Ranweli

Yasas Sri” (THC4) is a recently introduced high-yielding cardamom variety developed in Sri

Lanka. However, its chemical composition has not been reported yet. In this study,

hydrodistilled-essential oil profiles of THC4 were compared with export-grade Ceylon

cardamom (UWC2) using GC-MS and Raman spectroscopy. Chemical analysis using GC-MS

indicated that both UWC2 and THC4 contained high concentrations of α-terpinyl acetate

(37.48% and 37.81%, respectively), the primary compound responsible for the characteristic

sweet, floral aroma of cardamom and a key quality indicator. Higher linalool concentrations were

observed in THC4 (11.83%) compared to UWC2 (9.59%) with THC4 also containing linalyl

acetate (5.47%) contributing to a more refined floral profile. In contrast, elevated 1,8-cineole

levels were found in UWC2 (23.46% vs. 14.82%), indicating a 1.6:1 composition ratio between

two varieties. However, the reduced 1,8-cineole content in THC4 did not compromise quality,

but rather it enhances the aromatic balance. Raman spectroscopic analysis revealed characteristic

peaks that correlate with the major compounds identified by GC-MS. Prominent peaks at 467,

576, and 683 cm-1 correspond to ring deformation vibrations of 1,8-cineole and α-terpinyl

acetate. The peak at 1368 cm-1 represents symmetric and asymmetric bending vibrations of

methyl groups (CH3) directly attached to carbon-carbon double bonds (C=C) in unsaturated

compounds such as α-terpinene. Ring quadrant stretching vibrations of cyclic terpenes were

observed at 1605 cm-1, while the band at 1665 cm-1, attributed to C=O stretching, indicated the

presence of cyclic esters. Around 2870 cm-1, a complex peak arises from C-H, CH3, and CH2

stretching vibrations in aliphatic compounds, representing contributions from various terpenes,

esters, and alcohols including α-pinene, α-terpinyl acetate, 1,8-cineole, linalool, and limonene.

The compositional variations among cardamom varieties revealed by GC-MS results correlate

well with their respective Raman spectral patterns. Therefore, a Raman spectroscopic method

can be developed as a rapid, cost-effective tool for cardamom authenticity verification and

adulteration detection in quality control.

Neranga Abeyasinghe

University of Colombo