Defects PSE and DFD Meat

Rapid drops in ATP and pH (Fig. 12.24) cause pork muscle to become pale and soft and to undergo extensive drip loss because of lowered wa- 

PSE- Meat Pale, 5.6 exudative, loose soft texture 5.6 0.3 1.9 9.0 

The falling pH value and the high temperature cause protein denaturation. Soluble proteins precipitate and scatter light. Consequently, the meat appears paler in spite of the unchanged myoglobin content. At the same time, cell membranes disintegrate and water loss increases. In fact, PSE pork incurs up to 15% drip loss in 3 days and normal meat only ca. 4%. 

The occurrence of dark and firm pork meat (DFD meat dark, firm and dry) is likewise characteristic of a stress-impaired hog. Since glycogen is largely used up due to stress, only a little lactic acid is formed after slaughtering and the pH hardly falls (Fig. 12.24). The microfibrils which are more swollen at higher pH values bind more water (dry texture). As a result of this effect and the higher stabihty of oxymyoglobin at higher pH values (cf. 12.3.2.2.3), the color 

Data relating to normal and faulty cuts of meat are summarized in Table 12.14. Both defects mentioned may occur in different muscles of the same animal. The PSE effect is not significant in beef muscle tissue since energy is available from fat oxidation so glycogen breakdown can occur slowly. These meat defects may be avoided in hog muscles by careful handling of stress-sensitive animals and by rapid cooling of carcasses. 

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