ESR-based investigation of radiation-induced free radicals in fresh vegetables after different drying treatments

Abstract

Fresh vegetables, such as paprika, cucumber, and cabbage, were gamma-irradiated at 0, 2, and 5 kGy. Different pretreatments and selection of samples were compared to obtain improved electron spin resonance spectral features resulting in better detection of irradiation status. The non-irradiated samples exhibited a single central signal at about g0 = 2.007), whose intensity showed a significant increase upon irradiation. However, the irradiation also produced the typical electron spin resonance spectra of the radiation-specific cellulose radicals showing two side peaks (g1 = 2.023 and g2 = 1.986) with a mutual distance of 6 mT. The difference in electron spin resonance responses was observed while analyzing the different parts of the same vegetable. The flesh sample gave better spectral characteristics providing clear radiation-induced electron spin resonance signals. The effect of different drying pretreatments was also evident providing the comparable or improved results when using alcoholic-extraction as an alternative to the conventional freeze-drying technique. © 2014 Copyright Taylor & Francis Group, LLC.