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
Tender Intermediate Tough
Psoas major *Biceps femoris (sirloin) Deep pectoral
Infraspinatus Rectus femoris Latissimus dorsi
Gluteus medius Adductor Trapezius
Longissimus dorsi Semitendinosus Superficial pectoral
Triceps brachii Semimembranosus
*Biceps femoris (round)

PIGLT BRASS DLTS (sirloin)

PIGLT RASSB DLTS (round)

 

Top Ten "Tender" and "Tough" Cuts in Shear Force (pounds) from the National Beef Tenderness Survey
"Tender" cuts
 Shear force
"Tough" cuts
Shear force
Tenderloin steak 5.7
Top round steak
11.7
Top blade steak 6.7
Eye of round steak
 10.3
Top loin steak 7.2
Bottom round steak
 9.7
Rib roast 7.3
Rump roast
 9.5
Rib steak 7.4
Eye of round roast
 9.2
Ribeye steak 7.5
Chuck roll steak
 9.2
Chuck roll roast 7.6
Chuck tender steak
 9.0
Clod roast 7.9
Top round roast
 9.0
Round tip roast 7.9
Bottom round roast
 8.9
Top sirloin steak 8.0
Round tip steak
 8.9

Source: Morgan et al. (1991).

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 length 3.6 µm 1.8 µm
Muscle fiber diameter 40 µm 80 µm
Sarcomere/fragment 6 15
Amount of stromal protein 3 mg/g 8 mg/g
Size of elastin fibrils .6 µm 4.0 µm
Collagen solubility 28% 6%
Amount of marbling 7% 2%
Distribution of marbling extensive collected

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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Meat Science at Texas A&M University

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