Changes in lactic acid levels during thawing of lamb chops

Area of Science:

• Food Science
• Meat Science
• Biochemistry

Background:

• Ultimate pH is a critical indicator of meat quality.
• Frozen meat storage and thawing processes can influence meat characteristics.
• Lactate concentration is linked to post-mortem metabolism and pH development.

Purpose of the Study:

• To investigate the changes in muscle lactate concentration during the thawing of lamb loins.
• To determine the effect of ultimate pH on lactate dynamics during thawing.
• To assess the impact of thawing on the accuracy of meat pH measurements.

Main Methods:

• Lamb loins (n=20) with varying ultimate pH (5.5–6.4) were frozen (-20 °C) and thawed (+3 °C).
• Muscle lactate concentration in the m. longissimus lumborum was measured at specific temperatures during thawing (-20, -5, -2, 0, +2 °C).
• Correlation between temperature, lactate levels, and ultimate pH was analyzed.

Main Results:

• Lactate levels increased significantly at -2 °C during thawing compared to -20 °C.
• Low and intermediate pH meats showed higher lactate post-thaw, with the most pronounced increase in low pH samples.
• High pH meat exhibited stable lactate levels throughout the thawing process.
• Thawing caused a measurable change in meat pH, particularly in low pH samples.

Conclusions:

• Immediate pH measurement of frozen meat is recommended over post-thaw assessment.
• Thawing can alter meat pH, with the extent of change dependent on the initial ultimate pH.
• Understanding lactate dynamics during thawing is essential for accurate meat quality evaluation.