Oxidation and side-chain modifications decrease gastrointestinal digestibility and transport of proteins from salted...

Area of Science:

• Food Science
• Protein Chemistry
• Fish Processing

Background:

• Protein oxidation is a concern in food preservation.
• Myofibrillar proteins are key components of fish muscle.
• Oxidation affects protein structure and function.

Purpose of the Study:

• To investigate the impact of protein oxidation on bighead carp myofibrillar protein digestion.
• To characterize oxidation-induced modifications and their effect on digestibility and intestinal transport.

Main Methods:

• Assessing oxidation levels and in vitro digestibility of myofibrillar proteins from fresh-brined and frozen bighead carp.
• Analyzing peptide profiles and side-chain modifications using techniques like mass spectrometry.
• Evaluating intestinal transport properties of peptides.

Main Results:

• Frozen fish exhibited higher oxidation, lower amino acid content, and reduced in vitro protein digestibility.
• Brining further increased oxidation levels.
• Myosin heavy chain (MHC) showed significant peptide modifications, including Lysine/Arginine-MDA adducts, AAS, and GGS.
• These modifications decreased protein digestibility and intestinal transport.

Conclusions:

• Protein oxidation negatively affects myofibrillar protein digestibility and intestinal transport.
• Specific amino acid modifications are linked to reduced digestive properties.
• Findings highlight the importance of managing protein oxidation in fish processing and preservation.