Solid-like mechanical behaviors of ovalbumin aqueous solutions

Area of Science:

• Colloid and Surface Science
• Biophysical Chemistry
• Food Science

Background:

• Ovalbumin (OVA) is a primary protein in egg white, widely studied for its functional properties.
• Understanding the rheological and mechanical behavior of protein solutions is crucial for food processing and biomaterial applications.
• Existing theories like DLVO may not fully explain the behavior of concentrated protein solutions.

Purpose of the Study:

• To investigate the flow and dynamic mechanical properties of ovalbumin (OVA) aqueous solutions.
• To elucidate the forces stabilizing the structure of OVA solutions.
• To assess the applicability of conventional theories in explaining observed phenomena.

Main Methods:

• Steady shear rheometry to measure viscosity.
• Dynamic oscillatory shear rheometry to determine storage and loss moduli.
• Varying solution conditions to probe interparticle forces.

Main Results:

• OVA solutions exhibited high zero-shear viscosity, indicating significant resistance to flow.
• A consistent solid-like mechanical response (storage modulus > loss modulus) was observed across the tested frequency range.
• Solid-like behavior persisted even when electrostatic forces were minimized, suggesting other stabilizing forces.

Conclusions:

• Ovalbumin molecules in aqueous solutions likely form an ordered, colloidal crystal-like array.
• Large interparticle repulsive forces, not fully explained by DLVO theory, are key to stabilizing these structures.
• Non-DLVO forces play a significant role in the rheological properties of native OVA solutions.