128 Chapter 6
(actin) (Quinn et al. 1980 ). Meat and fat cells
are surrounded by connective tissue, which
denatures and shrinks between 50 – 65 ° C,
depending on age of the animal. The collagen
in connective tissue starts to dissolve in this
process between 55 and 85 ° C, again depend-
ing on the age of the animal.
By coagulation and shrinkage, water is
pressed out of myofi brils or proteins in
general and cooking loss occurs (Table
6.1 ). Cooking loss may increase to 45% or
60% of the total water (75%) in meat
(45%/75% = 0.6).drip loss of PSE pork (Honikel and Kim
1986 ). Between 40 and 50 ° C, some soluble
proteins in the sarcoplasm denature and
become insoluble, as can be seen also in the
paleness of PSE pork (dispersion of light, as
in milk). Whereas soluble proteins coagulate
(denature) into a random structure by heating,
fi brillar proteins shrink during denaturation
(Fig. 6.7 left side).
Both denatured protein structures encoun-
ter less space. Myofi bers consist of many
proteins, as can be seen in Figure 6.6. They
denature between 50 ° C (myosin) and 70 ° C
Figure 6.5. Scheme of myofi bers and the action of salt. A shows the myofi bers of meat with immobilized
water (background net structures in an aqueous environment); B shows salt - swollen meat myofi bers with more
immobilized water within the myofi bers; C shows that some myofi bers are dissolved in the aqueous environ-
ment with only a few immobilized water layers (thin lines along the fi bers).
Figure 6.6. Electron microscope picture of myofi bers in meat in their well - ordered structure.