Marbling in beef refers to the presence of intramuscular fat within the connective tissue layers of the meat, which enhances tenderness and flavor. This fat is distributed throughout the muscle, contributing to the overall quality of the meat. For instance, a typical grocery store steak exhibits some marbling, while Kobe beef, a renowned delicacy from Japan, showcases extreme marbling with fat interspersed throughout the muscle.

To understand where this excess fat is located, it is essential to recognize the three connective tissue layers within muscle: the epimysium, perimysium, and endomysium. The epimysium encases the entire muscle, but since marbling is found within the meat, it is not a significant contributor to marbling. The perimysium surrounds individual fascicles, and it is here that noticeable fat can be observed, especially in cuts of meat like Kobe beef. This layer likely contains the majority of the visible fat clumps.

Additionally, the endomysium surrounds each individual muscle fiber within the fascicle. Although this layer is microscopic, it may also contain fat, contributing to the marbling effect seen in high-quality beef. Therefore, when considering the structures where excess fat is found in Kobe beef, both the perimysium and endomysium are key players. Understanding these connective tissue layers not only enhances appreciation for the meat but also explains the rich flavor and tenderness associated with marbled beef.