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A new equation for converting EC 50 into TEAC values and TEAC into EC 50 is presented in this paper. The model was fitted to 180 data points of electron paramagnetic resonance (EPR) spectroscopy measurements of various food products. The model was tested basing on 75 EPR spectroscopy measurements. Moreover, the equation was tested on literature data. The determination coefficient between EC 50cal and EC 50exp was found to be R 2  = 0.9762, while the determination coefficient between TEAC cal and TEAC exp was found to be R 2  = 0.9686. Based on obtained results it can be concluded that the proposed model for converting EC 50 into TEAC values and TEAC into EC 50 values works properly. This will enable a comparison of the antioxidant properties of products identified in literature through the use of different parameters (TEAC, EC 50 ). [ABSTRACT FROM AUTHOR]

The antioxidant properties of various kinds of the traditional Polish alcoholic beverage nalewka were investigated using electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and ultraviolet–visible (UV–vis) spectroscopy. The antioxidant capacity was measured by EPR spectroscopy in μmol Trolox (TE) in a 100 mL nalewka sample. The total phenolic content was measured by Folin–Ciocalteu (FC) assays while aromatic proton content ( H ar ) was determined by NMR spectroscopy; subsequently the correlation among these values was explored. All of the investigated nalewkas exhibited antioxidant properties. The values of Trolox equivalent antioxidant capacity (TEAC DPPH ) were in the range 45–1045 μmol TE/100 mL. It was found that the value of the TEAC DPPH corresponded to the TP ( r = 0.96) and H ar ( r = 0.95). Moreover, the TEAC DPPH values depended on the kinds of fruits used for nalewkas’ preparation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The antioxidant properties of beer were investigated by means of EPR spectroscopy. [•] All beers studied have antioxidant properties. [•] The antioxidant capacity of beer depends on the extract content and colour. [•] The antioxidant activity of beer is not affected by its alcohol content. [Copyright &y& Elsevier]

Abstract: The antioxidant properties of samples of different kinds of commercially available alcoholic beverages were investigated by electron paramagnetic resonance (EPR) spectroscopy. This analytical technique is chiefly designed to enable accurate detection of free radicals. The determination of antioxidant activity by the EPR method is conducted by measuring the changes of the intensity of the EPR spectrum of stable radicals, which results from their interaction with antioxidants. Antioxidant capacity of alcoholic beverages samples was assessed with the use of the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH ). The highest antioxidant activity was found in red wines, followed by a blend of wine and brandy and then by whiskies, whereas plain vodkas and gin showed negative values of antioxidant activity. From our studies it can be concluded that the value of antioxidant capacity depends on the polyphenolic content, the time and method of ageing, as well as on the flavour and colour additives. [Copyright &y& Elsevier]