Development of voltammetric methods for the characterisation of natural antioxidants
Oxidant is an ion or a compound that reacts with a certain component of a living cell and oxidizes it. The reactive oxygen species produced in cells include hydrogen peroxide, hypochlorous acid, hydroxyl radical and superoxide anion. Antioxidant is a foreign substance that reacts with the oxidant faster than the components of the cell. An imbalance between oxidants and antioxidants in favour of the oxidants is termed oxidative stress. Antioxidants act as free radical scavengers and therefore can lower the risk of numerous degenerative diseases by preventing damages caused by free radicals. Fruits and vegetables are the major sources of antioxidants in human diet. Several natural compounds found in food, such as polyphenols, vitamins A and E, and some carotenoids, have been found to show excellent antioxidant activity. Chlorophylls and their derivatives have also been reported to possess this activity. However, literature is still scarce regarding their antioxidant properties. It is known that the amount of each antioxidant in fruits, vegetables and their derivatives is strongly influenced by numerous factors such as agro-technical processes, environmental conditions, processing factors and storage conditions. Continuous monitoring of antioxidant capacity of plant-based foods through different phases, from cultivation to storage, is needed to maintain or even improve the beneficial properties of food. The goal of this project is to develop several cyclic multi-pulse voltammetric techniques for the characterization of natural antioxidants and to apply them in routine analysis of food quality. Experimental results will be explained by the comparison with the theoretical simulation of responses of various electrode mechanisms of independent and conjugated multiple redox centers.