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The rheological properties of bovine β-Lactoglobulin stabilized oil/water interfaces depend on the protein’s quaternary structure

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posted on 2023-05-03, 19:22 authored by Sashikumar Ramamirtham, Catherine Whitby, Davoud Zare, Mike WeeksMike Weeks, Martin Williams
Structural manipulation of β-lactoglobulin through processes such as heat treatment and complexation with other molecules has proven fruitful in industrial formulations. To fully appreciate the ramifications of such methods on protein interfacial adsorption we have investigated assemblies of β-lactoglobulin at oil/water interfaces predominantly at pH 3 and at different conditions of ionic strength, salt type and temperature. These parameters were tuned to vary the relative amounts of two native species, namely, monomer and its smallest aggregate, the dimer, while the interface was monitored using rheology and tensiometry. Unfolding of β-lactoglobulin at the interface triggers the formation of disulfide linkages between the free thiol groups of two monomers which are located at cys121. In this way, monomers pair up to form discrete assemblies of two β-lactoglobulin molecules (non-native dimers) that are not interconnected further and this is reflected in the absence of a viscoelastic layer in solutions with high monomer concentrations. Native dimers however form primary particles capable of forming two thiol bonds allowing the formation of extended networks. A higher concentration of dimers increases the final interfacial elastic strength of the network. This fundamental relation between the quaternary structure of β-lg and its subsequent interfacial network suggests a possible interfacial role in its biological function.

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Rights statement

© 2021 Elsevier Ltd. All rights reserved.

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

Elsevier

Journal title

Food Hydrocolloids

ISSN

0268-005X

Citation

Ramamirtham, S., Whitby, C. P., Zare, D., Weeks, M., & Williams, M. A. K. (2021). The rheological properties of bovine β-Lactoglobulin stabilized oil/water interfaces depend on the protein’s quaternary structure. Food Hydrocolloids, 120, 106834. doi:10.1016/j.foodhyd.2021.106834

Funder

Ministry of Business, Innovation & Employment

Contract number

C10X1502

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