Electron spin resonance spectral analysis of irradiated royal jelly

• Published in: Food chemistry Vol. 143; pp. 479 - 483
• Main Authors: Yamaoki, Rumi, Kimura, Shojiro, Ohta, Masatoshi
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15-01-2014; Elsevier
• Subjects: Biological and medical sciences; Electron Spin Resonance Spectroscopy - methods; ESR; Fatty Acids - chemistry; Food Irradiation; Food Storage; Food toxicology; Gamma Rays; Irradiation; Medical sciences; Radiation-induced radical component; Royal jelly; Storage condition; Toxicology; Royal jelly; Irradiation; Radiation-induced radical component; ESR; Storage condition; Storage; Conservation; Radiation; Spectral analysis
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2013.07.139

•We detected radical components in irradiated fresh frozen royal jelly and dried powder.•The splitting asymmetric ESR line with overall spectrum width 10mT at g=2.004 was observed.•The ESR intensity increased in proportion to the absorbed dose.•The ESR intensity was highly stable and was distinguishable from that un-irradiated.•The radiation-induced radical was derived from the poorly soluble constituent.
The analysis of unpaired electron components in royal jelly was carried out using electron spin resonance (ESR) with the aim to develop a detection method for irradiated royal jelly. The ESR spectrum of royal jelly had natural signals derived from transition metals, including Fe3+ and Cu2+, and a signal line near g=2.00. After irradiation, a new splitting asymmetric spectrum with overall spectrum width ca. 10mT at g=2.004 was observed. The intensities of the signals at g=2.004 increased in proportion to the absorbed dose in samples under different storage conditions: fresh frozen royal jelly and dried royal jelly powder at room temperature. The signal intensity of the fresh frozen sample was stable after irradiation. One year after 10kGy irradiation of dried powder, the signal intensity was sevenfold greater than before irradiation, although the intensity continued to steadily decrease with time. This stable radiation-induced radical component was derived from the poorly soluble constituent of royal jelly.