Horse meat is a good source of iron with low cholesterol but consumers consider tenderness most important when purchasing meat. Myofibers and intramuscular connective tissue, the main structural components of muscle, play major roles in meat toughness. The effects of myofibers and perimysium characteristics on Warner-Bratzler Shear Force (WBSF) values of horse semimembranosus were investigated on muscles previously assessed as tough (mean WBSF 68.87 ± 3.21 N, n = 8) or tender (mean WBSF 46.21 ± 2.27 N, n = 8). Mean Type IIA myofiber diameter was significantly greater in tender than in tough muscles. Secondary thick perimysium was thicker and collagen fibers more loosely arranged in tender muscles than in tough. A negative correlation was observed between WBSF values and perimysium thickness and a trend between WBSF and intramuscular fat. Adipocytes in perimysium of tender muscles may have contributed to thickening of perimysium and loosened collagen fibers thus contributing to tenderness of the meat.

马肉是低胆固醇铁的良好来源，但消费者认为购买肉时嫩度最为重要。肌纤维和肌肉内结缔组织是肌肉的主要结构成分，在肉的韧性中起主要作用。在先前评估为坚韧的肌肉上调查了肌纤维和包膜特征对马半膜的Warner-Bratzler剪切力（WBSF）值的影响（平均WBSF 68.87±3.21 N，n = 8）或嫩（平均WBSF 46.21±2.27 N，n = 8）。IIA型平均肌纤维直径在嫩时明显大于在坚硬的肌肉中。次生较厚的肌膜较厚，胶原纤维比坚韧的肌肉更松散地排列在嫩肌中。观察到WBSF值与肌周厚度之间的负相关，以及WBSF与肌内脂肪之间的趋势。嫩肌皮膜中的脂肪细胞可能导致了皮膜的增厚和胶原纤维的松弛，从而导致了肉的嫩度。