Proteolysis in biceps femoris during Jinhua ham processing

Area of Science:

• Food Science
• Meat Science
• Biochemistry

Background:

• Traditional Jinhua ham processing relies on complex biochemical changes.
• Understanding muscle proteolysis is key to optimizing ham quality and flavor.

Purpose of the Study:

• To investigate the extent and nature of protein degradation during Jinhua ham processing.
• To analyze the resulting nitrogen fractions and free amino acids in biceps femoris muscle.

Main Methods:

• Analysis of nitrogen fractions (protein nitrogen, non-protein nitrogen) in biceps femoris.
• Quantification of free amino acids and peptide molecular weight distribution.
• Correlation of proteolysis patterns with muscle proteolytic enzymes.

Main Results:

• Over 10% of muscle proteins were degraded, with significant breakdown of both insoluble and soluble proteins.
• Non-protein nitrogen (NPN) increased, while protein nitrogen decreased (P<0.05).
• Over 90% of NPN products were free amino acids and peptides <1kDa, indicating intense degradation of larger peptides.

Conclusions:

• Intense proteolysis during Jinhua ham processing significantly alters muscle protein composition.
• The formation of free amino acids and small peptides is critical for Jinhua ham's characteristic taste and aroma.
• Muscle proteolytic enzymes likely play a pivotal role in these transformations.