This study investigated the dose-dependent effects of γ-irradiation (0-20 kGy) on caraway seed oil. Samples were analysed using GC-MS and GC-FID, tested against six microorganisms using agar diffusion assays, and evaluated by molecular docking analysis. Chemical analyses revealed marked compositional changes. At 5 kGy, saturated fatty acids increased from 32.27% to 63.08%, accompanied by a decline in unsaturated fractions, while limonene exhibited a transient increase to 26.82%. At higher doses (10-20 kGy), the volatile profile shifted, with carvone dominating (75.71-76.85%) and increased relative levels of oxygenated monoterpenes such as dihydrocarvone and limonene oxides. Antimicrobial activity varied with irradiation dose. Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were highly susceptible, showing inhibition zones up to 30.33 mm and 29.67 mm, respectively. Gram-negative bacteria exhibited reduced inhibition at 5 kGy but increased responses at higher doses, with Escherichia coli inhibition reaching 24.67 mm. Fungal strains showed limited inhibition with non-irradiated oil at lower concentrations, whereas irradiation at 10-20 kGy produced measurable inhibition zones ranging from 13 to 26 mm. Multivariate analysis associated the 5 kGy dose with altered fatty acid patterns and weaker antimicrobial responses, while treatments at 10-20 kGy correlated with oxygenated volatile constituents and stronger inhibitory effects. Molecular docking analysis was consistent with these trends, indicating more favorable interactions of carvone compared with limonene across selected microbial targets. Overall, γ-irradiation alters caraway seed oil chemistry in a dose-dependent manner, with higher doses associated with increased oxygenated volatiles and enhanced antimicrobial activity under the conditions of the assay.
Mohamed et al. (Fri,) studied this question.