Effect of irradiation, packaging, and postirradiation cooking on the thiamin content of chicken meat

The effect of irradiation with X rays or electrons, irradiation and storage temperature, and postirradiation cooking on the thiamin content of vacuum- or air-packaged minced chicken meat was examined. Samples irradiated with 3-kGy X rays (50 Gy/min) or electrons (5 kGy/min) contained less thiamin than the control specimens, but no differences between both irradiation methods were detected. The thiamin content in samples stored and/or irradiated at 5 degrees C was between 13 and 24 microg per 100-g product lower than in samples stored and/or ionized at -18 degrees C. The same difference in thiamin content was found for specimens packaged in a vacuum or air package, respectively. Vacuum packaging lead to a greater loss of drip than air-packaged samples. The biggest loss of thiamin, 31.1 and 28.0% for X rays and electron beams, respectively, was measured for vacuum-packaged specimens stored and irradiated at 5 degrees C. Compared with the cooked minced chicken breast meat, a higher thiamin content (6 to 17 microg of thiamin per 100-g product) was obtained for the raw samples. When irradiation and vacuum packaging were compared as two separate preservation techniques, the two methods had approximately the same effect on the thiamin content of the minced chicken meat. The mean temperature of the samples after cooking was 87.2 +/- 4.9 degrees C. However, significant differences in internal temperature after cooking of the samples were measured between air- and vacuum-packaged samples.