Context The texture of beef is highly important for the eating experience, and there is a continued interest in understanding the biochemical basis for the variation in texture between cattle and their meat cuts in order to improve and minimise variation in tenderness due to production and processing factors. Aims The present study aimed to investigate the impact of characteristics of meat on Warner-Bratzler shear-force (WBSF) as an indicator of texture of beef as affected by breed type, age/feeding phase, and muscle. Methods Seventy-five steers of three breed types (Angus, Hereford and Wagyu × Angus) were slaughtered after weaning 6 months old (n = 15), after backgrounding 17 months old (n = 30) and after feedlotting 25 months old (n = 30). At slaughter three muscles (M. supraspinatus, M. semitendinosus and M. longissimus lumborum) were sampled from each steer, and pH, intramuscular fat and collagen content, sarcomere length, and proteolysis (desmin degradation) were measured and used to explain the variation in WBSF after 7 and 14 days of aging. Key results Meat from Hereford and Angus steers had higher WBSF after 7 days of aging compared with Wagyu × Angus steers, but after 14 days of aging there was only a difference between Hereford and Wagyu × Angus in the M. supraspinatus and M. semitendinosus. The WBSF of the young weaned steers and steers slaughtered after backgrounding were dependent on the degree of proteolysis in the muscles, whereas for steers slaughtered after feedlotting the content of collagen was more important for the WBSF. The amount of intramuscular fat had a significant impact on the differences in WBSF within the specific muscle studied. In contrast to the general dogma that WBSF increase with age, WBSF decreased in M. semitendinosus and M. longissimus lumborum from the weaned 6-month-old steers to the 25-month-old steers finished in feed-lot, whereas in M. supraspinatus the older feed-lot finished steers had a higher WBSF. Conclusion The factors contributing to the Warner-Bratzler shear force of beef depends on the age/feeding phase of the animal and the muscle and less on the breed type. Implications Optimisation of texture in beef through breeding and production should address different traits dependent on the age/feeding phase of the slaughter animal.

中文翻译：

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胶原蛋白、肌内脂肪和蛋白水解作用在断奶、放牧后和饲养场后对 Bos taurus 肌肉的 Warner-Bratzler 剪切力产生不同的影响

背景 牛肉的质地对于食用体验非常重要，人们对了解牛与其肉块之间质地变化的生化基础一直很感兴趣，以改善和最小化由于生产和加工因素引起的嫩度变化. 目的 本研究旨在调查肉类特性对 Warner-Bratzler 剪切力 (WBSF) 的影响，作为牛肉质地的指标，受品种类型、年龄/喂养阶段和肌肉的影响。方法 3 种品种（安格斯、赫里福德和和牛 × 安格斯）的 75 头公牛在断奶 6 个月后（n = 15）、背景后 17 个月（n = 30）和育肥后 25 个月（n = 30)。在屠宰时，三块肌肉（冈上肌、半腱肌和 M. 腰最长肌）从每头公牛中取样，测量 pH 值、肌内脂肪和胶原蛋白含量、肌节长度和蛋白水解（结蛋白降解），并用于解释老化 7 天和 14 天后 WBSF 的变化。主要结果 与和牛 × 安格斯公牛相比，赫里福德和安格斯公牛的肉在陈化 7 天后具有更高的 WBSF，但在陈化 14 天后，赫里福德和和牛 × 安格斯公牛在冈上肌和半腱肌中只有差异。年轻断奶公牛的 WBSF 和背景后屠宰的公牛取决于肌肉中的蛋白水解程度，而对于育肥后屠宰的公牛，胶原蛋白的含量对 WBSF 更为重要。肌肉内脂肪的量对所研究的特定肌肉内 WBSF 的差异有显着影响。与 WBSF 随年龄增长而增加的一般教条相反，半腱肌和腰最长肌的 WBSF 从断奶 6 个月大的公牛到 25 个月大的肉牛饲养场结束，而在 M.冈上肌较老的饲养场成品公牛具有更高的 WBSF。结论 影响牛肉 Warner-Bratzler 剪切力的因素取决于动物的年龄/饲养阶段和肌肉，而较少取决于品种类型。影响 通过育种和生产优化牛肉质地应该解决取决于屠宰动物的年龄/饲养阶段的不同特征。从断奶 6 个月大的公牛到 25 个月大的公牛在饲养场完成的腰最长肌，而在 M. supraspinatus 中，较老的饲养场完成公牛具有更高的 WBSF。结论 影响牛肉 Warner-Bratzler 剪切力的因素取决于动物的年龄/饲养阶段和肌肉，而较少取决于品种类型。影响 通过育种和生产优化牛肉质地应该解决取决于屠宰动物的年龄/饲养阶段的不同特征。从断奶 6 个月大的公牛到 25 个月大的公牛在饲养场完成的腰最长肌，而在 M. supraspinatus 中，较老的饲养场完成公牛具有更高的 WBSF。结论 影响牛肉 Warner-Bratzler 剪切力的因素取决于动物的年龄/饲养阶段和肌肉，而较少取决于品种类型。影响 通过育种和生产优化牛肉质地应该解决取决于屠宰动物的年龄/饲养阶段的不同特征。结论 影响牛肉 Warner-Bratzler 剪切力的因素取决于动物的年龄/饲养阶段和肌肉，而较少取决于品种类型。影响 通过育种和生产优化牛肉质地应该解决取决于屠宰动物的年龄/饲养阶段的不同特征。结论 影响牛肉 Warner-Bratzler 剪切力的因素取决于动物的年龄/饲养阶段和肌肉，而较少取决于品种类型。影响 通过育种和生产优化牛肉质地应该解决取决于屠宰动物的年龄/饲养阶段的不同特征。