Meat Tenderness

Objectives:

(1) To identify the tender, intermediate and tough major muscles of the carcass.

(2) To demonstrate the reasons for differences in tenderness among muscles.

(3) To show the relative differences in chemical and histological measurements between tough and tender meat.

Reading material: Principles of Meat Science (4th ed.), Chapter 12, pages 233 to 246.


Relative rank in tenderness

TenderIntermediateTough
Psoas majorBiceps femoris (sirloin)Deep pectoral
InfraspinatusRectus femorisLatissimus dorsi
Gluteus mediusAdductorTrapezius
Longissimus dorsiSemitendinosusSuperficial pectoral
Triceps brachiiSemimembranosus
Biceps femoris (round)
Ramsbottom et al.
PIGLT BRASS DLTS (sirloin) or PIGLT RASSB DLTS (round)

Top ten "Tender" and "Tough" cuts in shear force (pounds) from the National Beef Tenderness Survey

"Tender" cutsShear force (pounds)"Tough" cutsShear force (pounds)
Tenderloin steak5.7Top round steak11.7
Top blade steak6.7Eye of round steak10.3
Top loin steak7.2Bottom round steak9.7
Rib roast7.3Rump roast9.5
Rib steak7.4Eye of round roast9.2
Ribeye steak7.5Chuck roll steak9.2
Chuck roll roast7.6Chuck tender steak9.0
Clod roast7.9Top round roast9.0
Round tip roast7.9Bottom round roast8.9
Top sirloin steak8.0Round tip steak8.9
Source: Morgan, J. B., J. W. Savell, D. S. Hale, R. K. Miller, D. B. Griffin, H. R. Cross, and S. D. Shackelford. 1991. National Beef Tenderness Survey. J. Anim. Sci. 69: 3274-3283.

Shear force = Pounds of force to shear one-half-inch cores, removed parallel to the muscle fibers, of cooked muscle from steaks and roasts.

Differences among muscles

  1. Actomyosin effect
  2. Background effect
  3. Bulk density or lubrication effect

Differences among muscles because:

Actomyosin effect

Sarcomere length

Muscle fiber diameter

Sarcomere/fragment

Background effect

Concentration of stromal proteins

Size of elastin fibrils

Solubility of collagen

Bulk density or lubrication effect

Amount of marbling

Distribution of marbling

 

Traits of "Tender" and "Tough" meat

Trait"Tender""Tough"
Sarcomere length3.6 µm1.8 µm
Muscle fiber diameter40 µm80 µm
Sarcomere/fragment615
Amount of stromal protein3 mg/g8 mg/g
Size of elastin fibrils.6 µm4.0 µm
Collagen solubility28%6%
Amount of marbling7%2%
Distribution of marblingExtensiveCollected

Additional factors affecting meat tenderness

1. Breed type

Bos indicus (Brahman, Sahiwal, etc.) breeds tend to be tougher than Bos taurus breeds (Angus, Hereford, etc.). Bos indicus has greater amounts of calpastatin, a protein that interferes with postmortem degradation of muscle.

2. Locomotive versus support muscles

Less connective tissue in support muscles.

3. Quality grade effects

Prime has more marbling than Choice and Choice has more than Select.

4. Degree of doneness

As meat is cooked to more advanced degrees of doneness, the tougher it will get. Marbling helps to “insure” acceptable tenderness at higher levels of doneness.



Review of Material — What the student should know:

(1) The fundamental factors related to differences in meat tenderness.

(2) The role that actomyosin effects, background effects, and bulk density/lubrication effects plays singularly or in combination in meat tenderness.

(3) The relative differences in numerical values between “tender” and “tough” meat.

 

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