title: Application of EPR spectroscopy to the examination of pro-oxidant activity of coffee.
abstract: Free radicals present in coffee may be responsible for exerting toxic effects on an organism. The objectives of this work were to compare free radicals properties and concentrations in different commercially available coffees, in solid and liquid states, and to determine the effect of roasting on the formation of free radicals in coffee beans of various origins. The free radicals content of 15 commercially available coffees (solid and liquid) was compared and the impact of processing examined using electron paramagnetic resonance (EPR) spectroscopy at X-band (9.3 GHz). First derivative EPR spectra were measured at microwave power in the range of 0.7-70 mW. The following parameters were calculated for EPR spectra: amplitude (A), integral intensity (I), and line-width (ΔBpp); g-Factor was obtained from resonance condition. Our study showed that free radicals exist in green coffee beans (10(16) spin/g), roasted coffee beans (10(18) spin/g), and in commercially available coffee (10(17)-10(18) spin/g). Free radical concentrations were higher in solid ground coffee than in instant or lyophilised coffee. Continuous microwave saturation indicated homogeneous broadening of EPR lines from solid and liquid commercial coffee samples as well as green and roasted coffee beans. Slow spin-lattice relaxation processes were found to be present in all coffee samples tested, solid and liquid commercial coffees as well as green and roasted coffee beans. Higher free radicals concentrations were obtained for both the green and roasted at 240 °C coffee beans from Peru compared with those originating from Ethiopia, Brazil, India, or Colombia. Moreover, more free radicals occurred in Arabica coffee beans roasted at 240 °C than Robusta. EPR spectroscopy is a useful method of examining free radicals in different types of coffee.
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Krakowian
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Dominik
authors.initials: D
authors.lastname: Skiba
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland; Department of Food and Nutrition, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Adam
authors.initials: A
authors.lastname: Kudelski
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Pilawa
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland. Electronic address: pawelramos@sum.edu.pl.
authors.forename: Paweł
authors.initials: P
authors.lastname: Ramos
authors.affiliation: Department of Biophysics, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Adamczyk
authors.affiliation: Department of Food and Nutrition, School of Pharmacy and Laboratory Medicine, Medical University of Silesia in Katowice, Jedności 8, 41-200 Sosnowiec, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Pawłowska-Góral
mesh_terms: D003069:Coffee / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005609:Free Radicals / Q000032:analysis*; D017382:Reactive Oxygen Species
chemical_list: D003069:Coffee; D005609:Free Radicals; D017382:Reactive Oxygen Species
keywords: Coffee; EPR spectroscopy; Free radicals