The Effect of Roasting on Flavour Profile of Ajwain seeds (Trachyspermum ammi ) & Cumin seeds (Cuminum cyminum)

Ajwain (Trachyspermum ammi ) and cumin (Cuminum cyminum) are widely used spices known for their characteristic aroma, flavour, and therapeutic properties. Roasting is a common culinary practice that enhances the sensory attributes of spices by modifying their volatile compounds and chemical composition. The present study aimed to evaluate the effect of roasting on the flavour profile and selected physicochemical properties of ajwain and cumin seeds.
The spices were subjected to controlled roasting at different temperature–time combinations, followed by extraction and analysis. Moisture content, colour parameters (L, a, b, ΔE), water activity (aw), and essential oil yield were determined for both raw and roasted samples. Sensory evaluation was conducted using a trained panel to assess aroma, flavour intensity, and overall acceptability of the spice extracts. The volatile flavour compounds were analysed using Headspace Solid Phase Microextraction coupled with Gas Chromatography–Mass Spectrometry (HS-SPME–GC–MS) and Nuclear Magnetic Resonance (NMR). Additionally, antioxidant activity of essential oils from raw and roasted samples was evaluated using the DPPH radical scavenging assay.
The results indicated that roasting significantly influenced the flavour profile of both spices. Roasting enhanced the release and concentration of key aroma compounds such as cuminaldehyde in cumin and thymol in ajwain, contributing to improved sensory characteristics. Changes in colour values and moisture content were observed with increasing roasting intensity, reflecting the occurrence of thermal reactions. Sensory evaluation results demonstrated that specific roasting conditions produced extracts with superior aroma and flavour attributes. The study highlights that controlled roasting can enhance the flavour characteristics and functional properties of ajwain and cumin, while excessive roasting may lead to degradation of important volatile compounds. The findings provide useful insights for optimizing roasting conditions to improve the flavour quality of these spices for culinary and industrial applications.