Kinetics of Oxidation and Antioxidation Processes in Biological Solutions Observed by NMR Relaxation

D. Wierzuchowskaa, M. Witekb, B. Blicharskac aInstitute of Physics, Pedagogical University, Podchorążych 2, 30-084 Kraków, Poland bDepartment of Refrigeration and Food Concentrates, Faculty of Food Technology, University of Agriculture in Krakow, Balicka 122, 30-149 Kraków, Poland cInstitute of Physics, Jagiellonian University, S. Łojasiewicza 11, 30-348 Kraków, Poland

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Preliminary studies on the application of NMR relaxation measurements for observations of the kinetics of oxidation processes in tea samples were performed. Tea is a rich source of flavonoids and other compounds with great antioxidant capacity and is therefore beneficial for human health. Its antioxidant potential depends on the type of tea and the method of preparation. Green and black tea prepared from tea bags brewed in water at 90° for 20 and 60 min were examined. Oxidation processes were induced in tea samples by adding 3% H2O2 in 1:10 proportion. Observed time courses of spin-lattice T1 relaxation time and parameters obtained from fitting of combined exponential and compressed-exponential function, depended on kind of tea, brewing time, and milk addition. The obtained results showed the usefulness of the NMR relaxation measurements for observation of oxidation processes and antioxidant activity.

DOI:10.12693/APhysPolA.137.21 topics: NMR relaxation, tea, oxidation processes, antioxidants' activity