A judgment on postmortem aging in longissimus dorsi based on a peptide substrate library

Area of Science:

• Food Science
• Biochemistry
• Meat Science

Background:

• Accurate determination of postmortem aging in meat is crucial for quality control.
• Protease activity is a key indicator of meat aging and texture changes.
• Existing methods for assessing meat aging can be time-consuming or lack precision.

Purpose of the Study:

• To develop a simple and effective method for determining pork postmortem aging.
• To utilize protease activity in the longissimus dorsi (LD) muscle as a biomarker for aging.
• To correlate protease activity with objective meat quality parameters.

Main Methods:

• Measurement of protease activity in pork LD muscle using fluorogenic peptide substrates.
• Quantification of fluorescence intensity changes over time.
• Correlation analysis between protease activity, muscle hardness, and free amino acid content.

Main Results:

• Strong positive correlations were observed between muscle hardness and fluorescence intensities against specific substrates (Ac-Ala-MCA, Ac-Met-MCA, Ac-Ser-MCA, Ac-Thr-MCA, Ac-Ala-Phe-MCA).
• Significant negative correlations were found between total free amino acids and fluorescence intensities against the same substrates.
• Negative correlations were also identified between specific free amino acids (Ala, Arg, Lys, Leu, Met, Phe, Tyr) and their corresponding fluorescence intensities.

Conclusions:

• Protease activity, measured via fluorogenic substrates, is a reliable indicator of postmortem aging in pork LD muscle.
• This method offers a potentially easy and effective way to assess meat quality and aging.
• The findings provide a biochemical basis for understanding texture changes during meat aging.