Volatile composition and antimicrobial properties of ground spices: Investigating the correlation using Principal Component Analysis

This study aimed to investigate the correlation between main detected volatile compounds and minimum inhibitory concentrations (MIC), which was further analyzed using principal component analysis (PCA). This is among the first studies to systematically link volatile compounds in ground spices to antimicrobial efficacy using PCA. The volatile components of various ground spices, including clove buds (Syzygium aromaticum), fennel seeds (Foeniculum vulgare), cumin (Cuminum cyminum), coriander (Coriandrum sativum), cardamom (Elettaria cardamomum), white pepper (Piper Nigrum), and cinnamon (Cinnamomum verum) were detected by GC-MS. Their antibacterial effects against selected pathogenic bacteria Escherichia coli, Staphylococcus aureus, and Bacillus subtilis were analyzed using a well-diffusion method to determine MIC. The results showed that 133 constituents were identified in those seven ground spices. The main identified volatile compounds were 1,8-cineole (80.86 %) in ground cardamom, while eugenol (61.64 %) was mainly found in ground clove buds. Furthermore, the major volatile compounds identified in ground fennel seeds, cinnamon, cumin, coriander, and white pepper were D-limonene (40.71 %), 1,8-cineole (28.52 %), β-pinene (30.39 %), 3-carene (36.66 %), and (+)-3-carene (37.68 %), respectively. Moreover, ground cinnamon and clove buds had the strongest antimicrobial activity against the selected bacteria, with MIC reaching 5 mg/ml, sufficient to inhibit the bacteria. The strong antimicrobial activity was related to the higher components of eugenol and 1,8-cineole identified from both spices. These results recommended the minimum concentration for the ground seeds once applied for antimicrobial food packaging to have better effectiveness in bacterial inhibition.