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 th an the control specimens, but no differences between both irradiation metho ds were detected. The thiamin content in samples stored and/or irradiated a t 5 degrees C was between 13 and 24 mu g per 100-g product lower than in sa mples stored and/or ionized at -18 degrees C. The same difference in thiami n content was found for specimens packaged in a vacuum or air package, resp ectively. 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 electr on beams, respectively, was measured for vacuum-packaged specimens stored a nd irradiated at 5 degrees C. Compared with the cooked minced chicken breas t meat, a higher thiamin content (6 to 17 mu g of thiamin per 100-g product ) was obtained for the raw samples. When irradiation and vacuum packaging w ere compared as two separate preservation techniques, the two methods had a pproximately the same effect on the thiamin content of the minced chicken m eat. The mean temperature of the samples after cooking was 87.2 +/- 4.9 deg rees C. However, significant differences in internal temperature after cook ing of the samples were measured between air- and vacuum-packaged samples.