Co-precipitates proteins prepared by soy and wheat: Structural characterisation and functional properties

Area of Science:

• Food Science
• Protein Chemistry
• Biochemistry

Background:

• Co-precipitation is a novel technique for enhancing protein functionality.
• Understanding the interaction mechanisms between soy protein isolate (SPI) and wheat protein (WP) is crucial for optimizing composite protein systems.

Purpose of the Study:

• To investigate the mechanism by which co-precipitation improves the functional properties of soy and wheat proteins.
• To determine the optimal ratio of SPI to WP for enhanced functional performance.
• To correlate protein structure and intermolecular forces with functional properties.

Main Methods:

• Isoelectric point co-precipitation was used to extract different protein proportions.
• Circular dichroism spectroscopy, disulfide bond analysis, and protein fraction extraction were employed to study interactions.
• Molecular modeling was utilized to understand protein linkages.
• Amino acid analysis assessed changes in nutrient content.
• Functional properties (emulsifying, foaming) were evaluated at various SPI:WP ratios.

Main Results:

• SPI and WP were primarily linked through non-covalent forces and disulfide bonds.
• Co-precipitation increased the lysine content of wheat protein.
• The composite system with a 7:3 SPI:WP mass ratio exhibited superior emulsifying and foaming properties compared to other ratios.
• Protein structure and intermolecular forces were found to significantly influence functional properties.

Conclusions:

• Co-precipitation effectively improves the functional properties of soy and wheat proteins.
• The 7:3 SPI:WP ratio is optimal for enhanced emulsifying and foaming capabilities.
• Protein structure and intermolecular forces are key determinants of functional performance in co-precipitated systems.
• This research offers valuable insights for developing novel protein-protein systems.