, 2006), biology (Pawłowska-Góral et al., 2013; Kurzeja et al., 2013), free radicals (Chodurek et al., 2012; Najder-Kozdrowska et al., 2010), techniques (Eaton et al., 1998; Wertz and Bolton,
1986), and biotechnology (Krztoń et al., 2009) is known. Our work is the fine example of usefulness of EPR spectroscopy in food biophysics. The obtained results broaden our knowledge about antioxidative properties of the famous herb—E. purpureae. The effect of UV irradiation on interactions of E. purpureae was not physically studied so far, and our proposition of EPR analysis in this example has the innovatory character. The important result was obtained: the interactions of E. purpureae with free radicals decrease after UV irradiation (Table 1; Fig. 3), and this herb should not be stored in exposition to UVA. Only the short time of UV irradiation (10 min) does not negatively influence on antioxidative properties of E. purpureae, when the EPR lines GDC-0973 price of DPPH did not increase check details relatively to the nonirradiated herb (Table 1; Fig. 3). EPR parameters of DPPH changed with time of UV exposition (Table 1; Figs. 3,
4), so the antioxidative ability of E. purpureae evolutes in time. E. purpureae losts its antioxidative properties during UV exposition in time. The interactions of E. purpureae with free radicals had a complex character, and this fact was reflected by the changes of linewidths (ΔB pp) (Fig. 4) and the asymmetry parameters (A 1/A 2, B 1/B 2, A 1 − A 2, and B 1 − B 2) of the DPPH spectra with time of UV irradiation (Table 1). These changes were not regular. The complex interactions are expected, because of the major transformations in E. purpureae under UV irradiation, when different chemical bonds may be broken and distances between unpaired electrons did not remain stable. The broadening Cell press of the EPR lines of DPPH interacting with E. purpureae is mainly caused by dipolar
interactions between freer radicals. The obtained results proved the possibilities of EPR studies of diamagnetic samples as E. purpureae by the use of paramagnetic probes—DPPH. The practical information about physical conditions of storage of E. purpureae was obtained. The economic aspects of EPR application in food biophysics were drawn. Conclusions The performed studies of E. purpureae by the use of an X-band (9.3 GHz) EPR spectroscopy proved that 1. Nonirradiated and UV-irradiated E. purpureae reveal antioxidant properties; it interacts with free radicals and as the result, it causes decrease of EPR signal of the paramagnetic reference—DPPH in ethyl alcohol solution. 2. UV irradiation changes interactions of E. purpureae with free radicals, and it decreases the antioxidative properties of this herb. 3. The interactions of E. purpureae with free radicals depend on time of UV irradiation. The weaker interactions of E. purpureae with free radicals Nirogacestat datasheet characterize the herb irradiated longer than 10 min (irradiated 20–110 min). 4.