ABSTRACT

This chapter focuses on biological aspects of Electron paramagnetic resonance (EPR) spectroscopy and discusses both theoretical and practical aspects of EPR. It outlines existing and potential applications of EPR spectroscopy to specific problems in food biochemistry and food analysis. Most free radicals are unstable molecules and will rapidly gain or lose an electron. They can be neutral, positively charged, or negatively charged species. In biological systems, free radicals often occur as transient intermediates in enzyme catalyzed reactions, most notably in electron transport, photosynthesis, and oxidation-reduction reactions. Triplet-state species are molecules that contain two strongly interacting unpaired electrons. Molecules containing two noninteracting or weakly interactly unpaired electrons are called biradicals and can be considered to be special cases of free radicals. The electron is a negatively charged particle of finite mass and its movement generates a magnetic field with an associated magnetic dipole moment. Two types of motion can be envisioned for an electron.