Liha töötlemine
resulting in the accumulation of metabolic anaerobic pathways, lowering pH. ATP is
byproducts, including lactic acid, in the rapidly consumed, but as reducing equiva-
muscle. The pH declines from about 6.8 to lents are consumed, it is not regenerated.
5.7. Endogenous thiol proteinases (cathep- Without the plasticizing effect of ATP, actin
sins B and L) become activated near pH 5.4. and myosin cross-link, the sarcomere short-
They are redistributed (intracellularly) during ens, fibers contract, and rigor results. During
aging (Spanier et al. 1990; Spanier and Miller the rigor process, muscle cells undergo both
1993). Proteolytic enzyme activity is temper- longitudinal and lateral contraction, usually
ature-dependent; some (cathepsins B and L) within 24 hours. WHC decreases during the
retain high activity levels even at cooking postmortem period. Rigor mortis occurs in
temperatures (70°C)
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