Structure-function modulation of sodium caseinate: Insights from non-covalent reuterin binding

Area of Science:

• Food Chemistry
• Protein Science
• Biomolecular Interactions

Background:

• Sodium caseinate (SC) is a widely used milk protein with functional properties crucial for food applications.
• Modulating SC structure can enhance its performance, but effective and non-damaging methods are sought.
• Reuterin (3-hydroxypropionaldehyde, 3-HPA) is a bioactive compound with potential applications in food systems.

Purpose of the Study:

• To investigate the impact of reuterin (3-HPA) on the structural and functional characteristics of sodium caseinate (SC).
• To elucidate the binding mechanisms and conformational changes induced by 3-HPA in SC.
• To assess the potential of 3-HPA as a molecular modulator for improving SC functionality.

Main Methods:

• Complex formation was analyzed using UV spectroscopy and SDS-PAGE.
• Structural changes were evaluated via FTIR and fluorescence spectroscopy, monitoring sulfhydryl and amino groups, and surface hydrophobicity.
• Computational simulations predicted interaction forces.
• Morphological and particle size analyses were performed using scanning electron microscopy and particle-size analyzers.

Main Results:

• SC/3-HPA complexes formed through non-covalent interactions, primarily hydrogen bonding and hydrophobic forces.
• 3-HPA induced significant conformational alterations in SC, decreasing sulfhydryl and amino group content and modifying surface hydrophobicity.
• Complexes exhibited reduced average particle diameter and smoother surfaces.
• SC treated with 3-HPA showed enhanced solubility, emulsifying activity, and foaming properties.

Conclusions:

• Reuterin (3-HPA) effectively modulates the structure of sodium caseinate (SC) via non-covalent interactions.
• 3-HPA treatment leads to significant structural changes in SC, enhancing its functional properties.
• 3-HPA shows promise as a novel molecular modulator for optimizing sodium caseinate in food applications.