Preponderance of cumin (Cuminum cyminum L.) essential oil constituents across cumin growing Agro-Ecological Sub Regions, India

• Cumin seed quality is significantly influenced by agro ecological conditions of growing areas.
• Relative presence of terpinene or aldehyde in cumin essential oil greatly influenced by environmental stresses.
• Cumin oil and oleoresin have potential commercial application in food and flavour industries.
• Desirable oil quality can be best obtained on the basis of AESRs evaluated in this study.
• Cumin seeds have potential anti-oxidant activity which can be explored for developing naturally occurring antioxidants.

Cumin seeds were collected from agro-ecological sub-regions comprising of major cumin growing areas of Rajasthan and Gujarat state, India, to analyze chemical composition of essential oil. The study area was located between the geographical co-ordinates 21°78′ 32″N, 71°33′85″E to 26°21′ 28″ N, 74°37′61″ E. Maximum and minimum EO yield (35.9–28.4%) were obtained in cumin from AESR 2.4 and 5.1 respectively. GC–MS analysis of EO indicated the preponderance of terpenic hydrocarbons in the AESR 2.4 (53.85%) and decrease in AESR 2.1 (32.62%) while cuminaldehyde content was more (39.90%) in AESR 4.2 and less (25.84%) in 2.4. The prominent terpenic compounds included γ-terpinene, β-pinene, santolina triene, α-terpinene, α-pinene and β-thujene, the concentration of these compounds varied with AESRs. Cumic alcohol (10.33–14.40%), anethol & estragol (4.03–9.15%) were the major alcohols with cymol (2.9–4.26%) and geraniol (0.02–2.39%) in traces. Total phenolic content in the various AESRs ranged from 41.50 (AESR 5.1) to 58.61 mg GAEg−1 seeds (AESR 2.3) while the flavonoid content in the AESRs ranged between 27.14–36.03 mg QE g−1 seeds, being least in 4.2 and highest in 5.1. The study revealed that the average radical scavenging percentage of methanol seed extract does not vary with the different AESRs (94.98–99.05%), as well as EC50 value is also same (15.31–15.38 mg BHTE) for samples from different AESRs. Cumin from the AESRs with favourable minimum and maximum temperature and rainfall showed high cuminaldehyde bearing pleasant aroma whereas the AESRs with biotic/abiotic stresses showed higher terpenic compounds with increased pungency.