Antioxidant Activity of Beer: An EPR Experiment for an Undergraduate Physical-Chemistry Laboratory

This laboratory experiment utilizes an exploration of the storage stability of beer to introduce basic aspects of electron-paramagnetic-resonance (EPR) spectroscopy. Radicals formed upon aerobic forced-aging of beer samples are established by using a spin-trap. The students are introduced to basic principles of EPR spectroscopy and food and radical chemistry with a simple example taken from everyday life. The methodology reported provides the students with valuable insights into EPR spectroscopy and the role of free radicals in food chemistry.