Handbook of Food Science and Technology 3

Figure 2.1.
Structure of muscle and connective tissue in meat 
Connective tissue 
Connective tissue is present at different levels in the muscle. The first 
layer, known as the 
endomysium
, consists of a thin sheath of connective 
tissue surrounding each individual muscle fiber. Groups of fibers form 
primary bundles that represent the “meat grain”. Meat grain size varies with 
species and breed: Limousine cattle have fine-grained meat whereas 
Charolais cattle have coarser-grained meat. A second sheath of connective 
tissue, known as the 
perimysium
, surrounds the primary bundles to form 
secondary bundles. Finally, the 
epimysium
, or facia, surrounds the secondary 
bundles to form the muscle. This connective membrane, thick and white, is 
visible on certain muscles and is generally removed by the butcher.
The connective tissue at the end of the muscle forms tendons. These 
attach muscle to bone and transmit forces from muscular contraction. 
Tendons are removed when trimming meat. 

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68 Handbook of Food Science and Technology 3 
Adipose tissue 
Muscle connective tissue contains adipocytes in the 
perimysium
; they 
form marbling, i.e. fat deposits visible to the eye. Apart from marbling, three 
types of adipose tissue can be found in a carcass: intramuscular fat, external 
fat that covers the carcass, and internal fat in the thoracic, abdominal and 
pelvic cavities (Figure 2.2).
Figure 2.2.
Structure of muscle, connective and adipose tissues in meat 
Fish
Fish muscle is also composed of muscle and connective tissue, but the 
structure is different to that of meat muscle. Interpenetration of these two 
tissues is not as pronounced in fish as it is in meat. In addition, fish muscle 
has a metameric structure. Fish flesh is composed of long muscles divided 
into conical segments, the top of which point towards the head (muscle 
tissue). These segments, also known as 
myotomes
, measuring 3 cm or less in 
length, are fitted into each other but remain separated by sheets of 
connective tissue known as 
myocommata
(Figure 2.3). When the connective 

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From Muscle to Meat and Meat Products 69 
tissue is separated from the myotomes, the individual flakes fall apart; this is 
known as splitting of gaping.