Interactions between β-lactoglobulin and casein glycomacropeptide on foaming

Area of Science:

• Food Science
• Colloid and Surface Science
• Protein Chemistry

Background:

• Casein glycomacropeptide (CMP) and β-lactoglobulin (β-lg) are major milk proteins with distinct properties.
• Understanding their interactions is crucial for optimizing food functionalities like foaming.
• Previous research has investigated their aqueous phase interactions using DLS and DSC.

Purpose of the Study:

• To investigate the impact of CMP:β-lg interactions on foaming properties.
• To evaluate the influence of pH (6.5 and 3.5) on the foaming performance of mixed CMP:β-lg systems.
• To correlate foaming behavior with previously observed inter-protein interactions.

Main Methods:

• Foaming properties were assessed using the bubbling method with a Foamscan instrument.
• Mixed systems with varying CMP:β-lg ratios were prepared.
• Foam capacity (FC), overall foam capacity (OFC), and foam stability were measured.

Main Results:

• Mixed CMP:β-lg foams exhibited significantly higher overall foam capacity, foaming capacity, and stability at pH 3.5 compared to pH 6.5 or individual protein foams.
• At pH 6.5, foam stability decreased with increasing CMP content, while OFC and FC were comparable to β-lg foams.
• The observed foaming performance was linked to the pH-dependent interactions between CMP and β-lg in the aqueous phase.

Conclusions:

• The interaction between CMP and β-lg significantly influences foaming properties, with a notable synergistic effect observed at acidic pH (3.5).
• pH is a critical factor governing the stability and capacity of mixed protein foams.
• These findings provide insights into tailoring protein-based foaming systems for specific food applications.