Electrical measurement for detecting early postmortem changes in porcine muscle

Area of Science:

• Meat Science
• Food Quality Assessment
• Electrical Impedance Spectroscopy

Background:

• Early detection of porcine muscle quality defects is crucial for the meat industry.
• Electrical properties of muscle change postmortem and correlate with quality traits.
• Understanding these changes can lead to improved quality control.

Purpose of the Study:

• To evaluate electrical measurements for detecting porcine muscle quality defects in the early postmortem period.
• To quantify interrelationships among electrical properties, pH, ATP decline, temperature, time, and water-holding capacity (WHC).
• To determine the predictive value of early electrical measurements for ultimate muscle quality.

Main Methods:

• Used a tetrapolar, constant current electrode configuration for low-frequency electrical measurements.
• Measured complex impedance, pH, ATP/IMP absorbance, and conductivity on porcine longissimus muscle (LM) over 10 hours postmortem.
• Assessed water-holding capacity (WHC), pH, conductivity (PQM), color, and subjective scores at 24 hours postmortem.

Main Results:

• Abnormal WHC groups showed more rapid onset and completion of rigor.
• Tecpro Pork Quality Meter (PQM) values were higher in abnormal groups at 90 minutes and 24 hours postmortem.
• Rate of change in impedance (Z*) and phase angle (theta*) within 15 minutes postmortem correlated with abnormal WHC, though one PSE sample showed a rapid decrease.

Conclusions:

• The rate of change in electrical impedance and phase angle before 90 minutes postmortem is a better predictor of ultimate porcine muscle quality than absolute impedance values.
• Electrical measurements offer a promising non-destructive method for early quality defect detection in pork.
• Further investigation into specific defect types (e.g., PSE) and their unique electrical signatures is warranted.