Chemiluminescence of cereal products II. Chemiluminescence spectra.
Spectra of ultraweak chemiluminescence (CL) accompanying auto-oxidation and hydration of cereal products have been measured using single photon counting and cut-off filters. The spectra cover the 380-880 nm spectral range with maxima centred around 600 nm. Analytically pure air-dried carbohydrates like agar, cellulose and nitrocellulose give emission too weak for spectral measurements. The emission from water pure carbohydrates is on average 4-12 times higher and emission spectra are similar to those from cereal products. The effect of free radical scavengers, SOD and O2* (1 delta g)-quenchers on CL spectra indicates a contribution of radical reactions with the participation of excited carbonyls, O2- and excited molecular oxygen dimoles. Moreover, possible mechanisms of chemi-excitation due to a cooperative H-bond formation during the hydration of carbohydrates and/or recombination of trapped radicals and electron-holes are discussed. It is also postulated that the excitation energy transfer to natural sensitizers occurring in cereal products may account for non-specific broad spectra and differences in the intensity of CL.
Słtawinska
D
D
Department of Physics, Agricultural University, Poznań, Wojska Polskiego, Poland.
Słtawinski
J
J
D001939:Bread / Q000032:analysis; D002523:Edible Grain / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry; D008163:Luminescent Measurements; D010084:Oxidation-Reduction; D010777:Photochemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D012434:Secale / Q000737:chemistry; D013057:Spectrum Analysis; D013482:Superoxide Dismutase / Q000737:chemistry; D014908:Triticum / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry
D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase