研究陕北横山羊肉宰后48 h内，不同部位肉块嫩度、持水性等相关指标的变化规律。分别在宰后4、8、12、24、48 h取背最长肌(HQ)和腹部肌肉(LQ)，测定了剪切力、汁液流失率和蒸煮损失率、肌浆蛋白和肌原纤维蛋白的溶解度、肌原纤维蛋白降解聚合情况。随着宰后时间延长，两类肉样剪切力在4～8 h显著增大(p<0.05)，12 h之后显著减小(p<0.05)；肉样汁液流失率、蒸煮损失率和肌浆蛋白溶解度均显著增加(p<0.05)；肉样肌原纤维蛋白溶解度4～12 h显著减小(p<0.05)而12 h之后逐渐增加(p<0.05)。在宰后过程中，HQ肉样剪切力、汁液流失率和蒸煮损失率显著小于LQ肉样(p<0.05)，肌浆蛋白溶解度显著高于LQ组(p<0.05)；在宰后12 h内，HQ肉样肌原纤维蛋白溶解度显著低于LQ组(p<0.05)，但20 h之后反超且显著高于LQ组(p<0.05)。两类肉样肌原纤维蛋白的SDS-PAGE电泳结果与溶解度变化趋势一致。宰后2 d内，横山羊肉的嫩度逐渐趋于嫩化，持水性减弱，稳定性减弱；背最长肌羊肉较低品质肉的嫩度和持水性较优、蛋白稳定性较差。

The changes of tenderness and water holding capacity of different grades Hengshan lamb meat slices from Northern Shaanxi province within 48 h after slaughter were studied. Longissimus muscle(HQ) and abdominal muscle (LQ) were measured at 4, 8, 12, 24 and 48 h after slaughter; the shear force and drip loss of sarcoplasmic and myofibrillar protein, cooking loss rate, solubility, myofibrillar protein degradation of polymerization were measured. With the time increases after slaughter, two kinds of meat shear force increased significantly in 4-8 h (p<0.05), meat drip loss significantly reduced, cooking loss rate and sarcoplasmic protein solubility were both significantly increased (p<0.05); pork myofibrillar protein solubility decreased significantly in 4-12 h but gradually increased after 12 hrs (p<0.05). After slaughter process, HQ meat shear force, drip loss and cooking loss rate were all significantly lower than that of LQ (p<0.05), sarcoplasmic protein solubility was significantly higher than that of LQ group (p<0.05); after 12 h, HQ myofibrillar protein solubility was significantly lower than that of LQ group (p<0.05), but after 20 hrs it was significantly higher than that of LQ (p<0.05). The SDS-PAGE results of two kinds myofibrils were consistent with the change of solubility. Within 2 days after slaughter, Hengshan mutton tenderness tends to be tender, its water holding capacity and stability decreased. For lower quality lamb meat from longissimus muscle, its tenderness and water holding capacity was good, but protein stability was poor.