Beta-lactoglobulin-dextran Maillard conjugates: their effect on interfacial thickness and emulsion stability

Area of Science:

• Food Science
• Colloid and Surface Science
• Bioconjugation Chemistry

Background:

• Beta-lactoglobulin-dextran Maillard conjugates are utilized as emulsifiers.
• Understanding the impact of polysaccharide molecular weight on conjugate properties is crucial for emulsion stability.

Purpose of the Study:

• To investigate how dextran molecular weight affects the steric layer thickness and emulsion flocculation stability of beta-lactoglobulin-dextran Maillard conjugates.
• To determine the relationship between conjugate structure and oil-in-water emulsion performance.

Main Methods:

• Formation of Maillard conjugates between beta-lactoglobulin and various molecular weight dextrans.
• Adsorption of conjugates onto latex spheres and measurement of adsorbed layer thickness using photon correlation spectroscopy.
• Assessment of emulsion stability against calcium-induced flocculation.

Main Results:

• Adsorbed layer thickness increased with dextran molecular weight, from 3 nm for beta-lactoglobulin alone to 20 nm for high molecular weight dextran conjugates.
• Enzymatic digestion confirmed the protein anchors the conjugate to the interface.
• Dextran attachment, regardless of molecular weight, enhanced emulsion stability against calcium-induced flocculation.

Conclusions:

• Dextran molecular weight dictates steric layer thickness and emulsion stabilization efficacy.
• Low molecular weight dextran is sufficient for achieving high steric stability in oil-in-water emulsions.
• The findings suggest universality across globular proteins due to dextran's role in controlling steric layer size.