Identification and characterization of gamma-irradiated dried Lentinus edodes using ESR, SEM, and FTIR analyses.
A detailed electron spin resonance (ESR) analysis for different parts of gamma-irradiated (0 to 50 kGy) dried mushroom (Lentinus edodes) was conducted to identify radiation-induced signals. All studied mushroom parts except gills produced strong dose-dependent radiation-induced ESR signals particularly at about g = 2.0076, 20005, and 1.9911 demonstrating the generation of crystalline sugar radicals following irradiation. The intensity of these signals was highest in cap skin samples, followed by the cap core, stem skin, whole mushroom powder, and stem core samples, respectively. ESR-based identification was easily possible at 2 kGy or more using mushroom cap skin or cap core as samples. The radiation-induced ESR signals were found sensitive to thermal treatment showing the limitation of ESR-based detection in case of heat-processed samples. Scanning electron microscopy (SEM) showed micro-structural damage upon irradiation resulting decreased percentage of rehydration; however, no major alteration was observed through the Fourier transform infrared (FTIR) spectra. Irradiation changed the structural morphology; however, the main functional groups were stable against radiation treatment.


CONCLUSIONS
Food irradiation can confirm hygienic quality and prolong the product shelf life. However, due to lack of international consensus, effective identification methods and detailed quality characterization are required for the general use of this technology.
Dept of Food Science & Technology, Kyungpook Natl Univ, Daegu 702-701, Republic of Korea.
Kashif
K
Akram
Jae-Jun
JJ
Ahn
Joong-Ho
JH
Kwon
D004040:Dietary Carbohydrates / Q000032:analysis; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy; D005504:Food Analysis / Q000379:methods*; D005511:Food Handling; D005514:Food Irradiation / Q000379:methods; D057141:Food, Preserved / Q000032:analysis* / Q000528:radiation effects*; D005609:Free Radicals / Q000032:analysis; D005720:Gamma Rays; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D011786:Quality Control; D056910:Republic of Korea; D020942:Shiitake Mushrooms / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014867:Water / Q000032:analysis
D004040:Dietary Carbohydrates; D005609:Free Radicals; D014867:Water