School of Veterinary Medicine and Animal Science, São Paulo State University, Botucatu (São Paulo); School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal (São Paulo);
School of Agricultural and Veterinary Sciences, São Paulo State University, Jaboticabal (São Paulo).
J Vis Exp. 2024 Jul 12(209). doi: 10.3791/66764.
This study investigated muscle tissue in Bos indicus and crossbred bulls to explain differences in meat quality traits. Carcass traits, meat quality parameters, and biochemical and molecular investigations of myofibrillar proteins are described. Methods for evaluating pH, intramuscular fat (IMF), meat color (L*, a*, b*), water losses, tenderness, and molecular biology assays have been outlined. Specific procedures detailing calibration, sample preparation, and data analysis for each method are described. These include techniques such as infrared spectroscopy for IMF content, objective tenderness assessment, and electrophoretic separation of MyHC isoforms. Color parameters were highlighted as potential tools for predicting beef tenderness, a crucial quality trait influencing consumer decisions. The study employed the Warner-Bratzler shear force (WBSF) method, revealing values of 4.68 and 4.23 kg for Nellore and Angus-Nellore (P < 0.01), respectively. Total cooking losses and biochemical analyses, including myofibril fragmentation index (MFI), provided insights into tenderness variations. Muscle fiber types, particularly myosin heavy chain (MyHC) isoforms, were investigated, with a notable absence of MyHC-IIb isoform in the studied Zebu animals. The relationship between MyHC-I and meat tenderness revealed divergent findings in the literature, highlighting the complexity of this association. Overall, the study provides comprehensive insights into the factors influencing meat quality in Bos indicus and crossbred (Bos taurus × Bos indicus) bulls, offering valuable information for the beef industry.
本研究旨在探究瘤牛和杂交公牛的肌肉组织，以解释肉质特性的差异。文中描述了胴体特性、肉质参数、肌原纤维蛋白的生化和分子研究。还概述了评估 pH 值、肌内脂肪（IMF）、肉色（L*、a*、b*）、水分损失、嫩度和分子生物学分析的方法。详细说明了每种方法的校准、样品制备和数据分析的具体程序。这些方法包括用于 IMF 含量的红外光谱、客观嫩度评估和 MHC 同工型电泳分离等技术。颜色参数被强调为预测牛肉嫩度的潜在工具，嫩度是影响消费者决策的关键质量特性。该研究采用 Warner-Bratzler 剪切力（WBSF）方法，发现内罗尔牛和安格斯-内罗尔牛的剪切力值分别为 4.68 和 4.23 kg（P < 0.01）。总蒸煮损失和生化分析，包括肌纤维小片化指数（MFI），提供了嫩度变化的见解。研究了肌纤维类型，特别是肌球蛋白重链（MyHC）同工型，发现在研究的瘤牛动物中不存在 MyHC-IIb 同工型。MyHC-I 与肉质嫩度之间的关系在文献中存在分歧，这突出了这种关联的复杂性。总的来说，本研究提供了对瘤牛和杂交（Bos taurus × Bos indicus）公牛肉质特性影响因素的全面了解，为牛肉产业提供了有价值的信息。
