Modelling post-mortem tenderisation-II: Enzyme changes during storage of electrically stimulated and non-stimulated...

Area of Science:

• Meat Science
• Biochemistry
• Food Technology

Background:

• Proteolytic enzymes play a crucial role in meat tenderization.
• Calpains are key enzymes involved in post-mortem muscle changes.
• Understanding enzyme activity under different storage conditions is vital for meat quality.

Purpose of the Study:

• To investigate the impact of storage temperature on calpain I, calpain II, cathepsins, and β-glucuronidase activity in beef.
• To determine the relationship between calpain I degradation and beef tenderization rates.
• To assess the stability of lysosomal enzymes during meat storage.

Main Methods:

• Beef M. Pectoralis profundus samples were subjected to electrical stimulation or control conditions.
• Meat was stored at temperatures ranging from 0 to 30°C to prevent muscle shortening.
• Enzyme activity (calpains I and II, cathepsins B and L, β-glucuronidase) was measured in extracts over time.

Main Results:

• Lysosomal enzyme levels remained stable throughout storage.
• Calpain II levels showed a slight decrease with ageing and were unaffected by initial treatments.
• Calpain I activity decreased significantly at higher temperatures (accelerated loss above pH 6.2), with decay rates correlating to tenderization rates.

Conclusions:

• Calpain I degradation rate is directly linked to the rate of beef tenderization.
• Storage temperature significantly influences calpain I stability and meat tenderization.
• Lysosomal enzymes and calpain II are less critical factors in temperature-dependent tenderization compared to calpain I.