BACKGROUND This study aimed to identify relationships between components of intramuscular connective tissue, the proportions of the different fiber types, intramuscular fat and sensory tenderness of beef cooked at 55°C. For that, four muscles differing in their metabolic and contractile properties as well as in their collagen content and butcher value, from dairy and beef cattle of several ages and sexes were used in order to create variability. RESULTS Correlation analyses and/or stepwise regressions were applied on Z-scores to identify the existing and robust associations. Tenderness scores were further categorized into tender, medium and tough classes using unsupervised learning methods. The findings revealed a muscle-dependant role on tenderness of total and insoluble collagen, cross-links and of type IIB+X and IIA muscle fibers. The Longissimus thoracis and Semitendinosus muscles that, in this study, were extreme in their tenderness potential were very different from each other and of the Rectus abdominis (RA) and Semimembranosus (SM). RA and SM muscles were very similar for their relationship for muscle components and tenderness. A relationship was present between marbling and tenderness only when the results were analysed irrespective of all the factors of variations of experimental model that are muscle and animal type. CONCLUSION The statistical approaches applied in this trial performed using the z-scores allowed to identify the robust associations between muscle components and sensory beef tenderness and also to found discriminatory variables of beef tenderness classes. This article is protected by copyright. All rights reserved.

中文翻译：

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结缔组织成分、肌肉纤维和大理石花纹对胸最长肌、腹直肌、半膜肌和半腱肌的牛肉嫩度变异性的贡献

背景本研究旨在确定肌肉内结缔组织成分、不同纤维类型的比例、肌肉内脂肪和 55°C 烹制牛肉的感官嫩度之间的关系。为此，使用了来自不同年龄和性别的奶牛和肉牛的四种在代谢和收缩特性以及胶原蛋白含量和屠宰量方面不同的肌肉，以产生可变性。结果 相关分析和/或逐步回归应用于 Z 分数以识别现有的和稳健的关联。使用无监督学习方法将柔软度分数进一步分为柔软、中等和坚硬的等级。研究结果揭示了对总和不溶性胶原蛋白、交联以及 IIB+X 和 IIA 型肌纤维的压痛的肌肉依赖性作用。在这项研究中，胸最长肌和半腱肌的压痛潜力非常大，它们彼此之间以及腹直肌 (RA) 和半膜肌 (SM) 都非常不同。RA 和 SM 肌肉在肌肉成分和压痛方面的关系非常相似。仅当分析结果时，不考虑肌肉和动物类型的实验模型的所有变化因素，大理石花纹和压痛之间存在关系。结论 本试验中应用的统计方法使用 z 分数进行，可以识别肌肉成分和感官牛肉嫩度之间的强大关联，并发现牛肉嫩度类别的判别变量。本文受版权保护。版权所有。