The object of presented study was the evaluation of antioxidant activity of extract from Zingiber officinale. A method for the preparation of the extract was chosen, which enabled to isolate mostly phenolic compounds. According to the measurements with Folin-Ciocalteu reagent, obtained extract comprised total polyphenols (181.41 mg_GAE/g of extract) from which flavonoids contributed to 7.8 % (14.15 mg_quercetin/g of extract). Nuclear magnetic resonance (NMR) analysis showed that the phenolic ketones were predominant in the extracts of whole phenolic compounds. According to results of two spectrophotometric methods (ABTS and DPPH test), ginger extract showed stronger ability to scavenge DPPH radical than ABTS cation radical.

The evaluation of antioxidant potential of food has received much attention in recent years. Antioxidant compounds can scavenge free radicals and thereby can protect the human body from free radicals. This study was focused on the isolation of curcuminoids from the dried turmeric rhizome, and studying their antioxidant activity. The presence of curcuminoids was identified in turmeric sample by Nuclear Magnetic Resonance (NMR) analysis. Since neutral curcumin is known to be poorly soluble, the synthesis of curcumin-cyclodextrin and curcumin-phospholipid complexes was also performed. The antioxidant activity of isolated curcuminoids was assessed by two methods (ABTS and FRAP assay) and their scavenging activities were compared with those of prepared complexes. The ability to reduce ABTS radical cation decreased as follows: quercetin > trolox > curcuminoids > curcumin-cyclodextrin complex > curcumin-phospholipid complex. The reducing potential of tested samples in descending order was quercetin > trolox > curcumin-cyclodextrin complex > curcuminoids > curcumin-phospholipid complex.

The efficacy of multi-hollow surface dielectric barrier discharge treatment against Escherichia coli, Salmonella Enteritidis and Bacillus subtilis was studied. Ambient air, O_2, and N₂ were used as working gas with a flow rate of 6 l/m. Power delivered into plasma was 30 W over an area of 2 × 2 cm². The active species in plasma generated in different gases participating in the inactivation of microorganisms were evaluated by optical emission spectroscopy and Fourier transform infrared spectroscopy. Inactivation curves were fitted to the Bigelow log-linear, the biphasic, and Geeraerd models. According to the results, all plasma treatments inactivated tested microorganisms, depending on a working gas. The most sensitivity of bacteria was observed to the ambient air plasma. Inactivation up to 5 log for E. coli and S. Enteritidis could be achieved within 15 s of plasma treatment. Air plasma exposure of 25 s also led to log₁₀ CFU/ml of B. subtilis from 7.98 to 4.39. S. Enteritidis was slight resistance to plasma treatment with N₂. Within 180 s nitrogen plasma treatment, a 2.04 log₁₀ CFU/ml reduction was recorded.