Abstract：
This study evaluates longitudinal and transversal intramuscular variations in muscle fiber and meat quality characteristics in bovine M. longissimus thoracis et lumborum (LTL). The LTL muscles (n = 5) from the left side of the beef carcass were cut at intervertebral segment intervals (between 1st thoracic vertebra (TV) and 6th lumbar vertebra (LV)). The pennation angle demonstrated an increasing trend from the anterior to posterior regions regardless of the medial (M-zone) and lateral (L-zone) regions (P < 0.05). The M -zone had a higher pennation angle than the L-zone in the TV and 1st LV (P < 0.05). The cross-sectional area (CSA) of muscle fibers, excluding type I, was larger in the posterior region than the anterior region (P < 0.05). A larger CSA of type I/IIA, IIA, IIAX, and IIX was observed on the lateral side than on the medial side of the 13th TV (P < 0.05). Fiber types were more oxidative (types I and IIA) in the anterior region and more glycolytic (types IIA/IIX and IIX) in the posterior region. Fat content was higher in the anterior region than in the posterior region (P < 0.05). The lowest redness, yellowness, and Warner-Bratzler shear force values were observed in the middle of the muscle, whereas the lightness value was lower in the posterior region regardless of the transversal region (P < 0.05). Therefore, bovine LTL muscles exhibit unique morphological properties and contribute to understanding meat quality associated with morphological and muscle fiber characteristics in relation to their intramuscular variations.
摘要：
这项研究评估了牛胸肌和腰肌（LTL）中肌肉纤维和肉品质特征的纵向和横向肌内变化。以椎间段间隔（在第1胸椎（TV）和第6腰椎（LV）之间）切割牛肉car体左侧的LTL肌肉（n=5）。与内侧（M区）和外侧（L区）区域无关，悬垂角显示出从前部到后部区域的增加趋势（P<0.05）。在TV和第一LV中，M区的悬垂角高于L区（P<0.05）。肌纤维的横截面积(CSA),不包括类型I，后部区域大于前部区域(P<0.05)。更大的I/IIA型CSA，IIA,IIAX,在第13个电视的外侧观察到IIX，而在内侧观察到IIX（P<0.05）。纤维类型在前部区域的氧化性（I型和IIA型）更高，而在后部区域的糖酵解性（IIA/IIX型和IIX型）更高。前区脂肪含量高于后区(P<0.05)。最低的发红，黄色,和Warner-Bratzler在肌肉中间观察到剪切力值，而无论横向区域，后部区域的亮度值均较低（P<0.05）。因此,牛LTL肌肉表现出独特的形态特性，有助于了解与肌肉内变化有关的形态和肌肉纤维特征相关的肉质。
