Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
Poult Sci. 2014 Aug;93(8):2087-95. doi: 10.3382/ps.2013-03248. Epub 2014 Jun 3.
This study was designed to compare the effects of different stunning systems on the meat quality of broilers. This was done by investigating meat water-holding capacity, meat color, muscle glycogen, and lactate concentrations, as well as blood parameters, low-field nuclear magnetic resonance (NMR) transverse relaxation, and myofibrillar ultrastructures. A total of 160 broilers were divided into 4 treatment groups: a low-voltage stunning (LS) with a constant voltage of 15 V at 750 Hz for 10 s; a midvoltage stunning (MS) with a constant voltage of 50 V at 50 Hz for 10 s; a high-voltage stunning (HS) with a constant voltage of 100 V at 50 Hz for 5 s; and a control group with no stunning (NS). Blood samples were collected immediately after cutting the neck. Pectoralis major muscles were removed from the carcass after chilling and placed in ice. Breast muscle pH, meat color, glycogen, and lactate contents were determined at both 2 and 24 h postmortem. Drip loss, cooking loss, pressing loss, cooked breast meat shear values, low-field NMR, and ultrastructures of myofibrils were determined 24 h postmortem. The NS and MS treatments significantly increased (P < 0.05) blood plasma corticosterone, initial rate of glycolysis, and drip loss, and significantly reduced (P < 0.05) initial muscle pH and shear force values when compared with LS and HS. The results of low-field NMR reflect that NS and MS significantly decreased (P < 0.05) NMR transverse relaxation population 1 (T21) and increased (P < 0.05) NMR transverse relaxation population 2 (T22). The myofibrils of NS and MS samples showed significantly (P < 0.05) longer sarcomere length when compared with the LS and HS samples. The meat color, cooking loss, pressing loss, and final pH were not affected by the stunning methods. This study indicates that NS and MS treatments reduce meat water-holding capacity and decrease meat shear force when compared with LS and HS.
本研究旨在比较不同致晕系统对肉鸡肉质的影响。通过研究肉的水分保持能力、肉色、肌肉糖原和乳酸浓度以及血液参数、低场核磁共振（NMR）横向弛豫和肌纤维超微结构来进行。总共 160 只肉鸡被分为 4 个处理组：低电压致晕（LS），电压为 15 V，频率为 750 Hz，持续 10 s；中电压致晕（MS），电压为 50 V，频率为 50 Hz，持续 10 s；高电压致晕（HS），电压为 100 V，频率为 50 Hz，持续 5 s；对照组不进行致晕（NS）。在切割颈部后立即采集血液样本。冷却后从胴体上取下胸大肌，置于冰上。在死后 2 和 24 小时测定胸肌肉 pH 值、肉色、糖原和乳酸含量。在死后 24 小时测定滴水损失、蒸煮损失、压榨损失、煮熟的鸡胸肉剪切值、低场 NMR 和肌纤维超微结构。与 LS 和 HS 相比，NS 和 MS 处理显著增加（P < 0.05）了血浆皮质酮、初始糖酵解速率和滴水损失，显著降低（P < 0.05）了初始肌肉 pH 值和剪切力值。低场 NMR 的结果反映出 NS 和 MS 显著降低（P < 0.05）了 NMR 横向弛豫群体 1（T21），增加了（P < 0.05）了 NMR 横向弛豫群体 2（T22）。与 LS 和 HS 相比，NS 和 MS 样本的肌纤维显示出明显更长的肌节长度（P < 0.05）。致晕方法对肉色、蒸煮损失、压榨损失和最终 pH 值没有影响。本研究表明，与 LS 和 HS 相比，NS 和 MS 处理降低了肉的水分保持能力，降低了肉的剪切力。
