Detection of caraway and bay leaves irradiation based on their extracts’ antioxidant properties evaluation

Antioxidant properties of extracts prepared from native (non-irradiated) ground caraway (Carum carvi, L.) and bay leaves (Laurus nobilis, L.) samples, as well as from those γ-irradiated by Co60 source at doses from 5 to 30 kGy were studied by EPR and UV–VIS spectroscopy, and expressed as Trolox Equivalent. Ferric reducing power, thiobarbituric acid reactive substances and total phenolic compounds content of each extract were characterised, as well. In addition, character of radicals formed upon the γ-irradiation in solid phase was studied by means of EPR spectroscopy. For the first time, multivariate statistical methods were used for γ-irradiation detection. The experimental data obtained from UV–VIS and EPR, were successfully used in canonical, step-wise and kth-neighbour discriminant analyses for the differentiation and classification of γ-irradiated samples from those of reference. More than 92% predictability of γ-irradiation was achieved by cross-validation tests for both caraway and bay leaves samples, exposed even at low radiation doses.