为探究电子束剂量率对充氮包装冷却牛肉微观结构、蛋白品质及感官特性的影响，取牛背最长肌，在高能电子加速器下辐照处理，4 ℃贮藏25 d。评估辐照剂量率和贮藏时间对其微观结构、蛋白品质及感官特性的影响。在贮藏初期，试验组和对照组相比，冷却肉表面色泽较暗，具有一定的辐照异味，感官得分相对较低，随着贮藏时间的延长，对照组的感官得分下降，辐照处理组相对稳定，150 kGy/min处理组感官得分相对较高。辐照处理可以在一定程度上加速冷却牛肉的成熟，150 kGy/min辐照处理对肌节长度的影响与未辐照处理组贮藏成熟15 d对肌节长度的影响相近。电子束辐照对冷却牛肉蛋白质含量及氨基酸组分无显著性影响，而贮藏时间对赖氨酸和缬氨酸等必须氨基酸的含量有显著性影响。

To evaluate the effect of electron beam dose rate on the ultrastructure, protein quality, and sensory characteristics of chilled beef, Longissimus dorsi muscles obtained from Chinese Yellow Cattle were irradiated at 2.5 kGy with dose rates of 30, 150, 300 kGy/min using a high-energy electron accelerator. The samples were stored at 4 ℃ to determine the effects of dose rate and storage time on the values of color, odor, ultrastructure, protein content, and amino acid component of the chilled beef at each storage period. At the beginning of storage, a comparison of the experimental and control groups demonstrated that the irradiated samples had a darker color, an off-odor, and a lower sensory evaluation score. However, with a prolonged storage time, the overall quality of the control samples decreased, while those of irradiated samples remained relatively stable. The quality of the chilled beef exposed to 150 kGy/min was better than that in the other irradiation groups. Irradiation accelerated aging of the beef meat. The effect of 150 kGy/min irradiation on sarcomere length was similar to the influence of 15 d of storage. The irradiation technique did not affect the protein content and amino acid component of the chilled beef. However, the amounts of lysine, valine, and other essential amino acids were affected by the storage time.

国家科技支撑计划课题（2014BAA03B05）；公益性行业（农业）科研专项经费资助项目（201103007）