Thermostable conformational transition unfavorable to the foaming stability of ovalbumin: Emphasizing structure and function relationship.

Storage of shell eggs converts natural ovalbumin (N-OVA) into its more thermostable forms (S-OVA). This conversion may be associated with deterioration in the foaming properties of the stored shell egg. Thus, the foaming behavior of N-OVA and S-OVA, especially their performance at different pH conditions, was conducted. Compared with N-OVA, S-OVA improved foaming ability by 29.04 % at pH 3.0 and exhibited rough foam. Regarding foaming stability, the conversion of N-OVA to S-OVA had a pronounced reduction effect, with foaming stability significantly decreasing by 28.48 %-100.00 % in pH 3.0-9.0. The spectroscopic analysis revealed that the alteration in the foaming properties of OVA was fundamentally attributed to its conformational change. Thermostable conformational transition provided S-OVA with smaller particle sizes, more flexible conformations, higher surface charge, and higher surface hydrophobicity. S-OVA at pH 3.0 showed a higher surface activity, indicating superior foaming ability. Moreover, N-OVA and S-OVA formed stiff and solid-like interfaces. Notably, N-OVA exhibited higher dilatational and elastic modulus, indicating a more compact and stable adsorption layer at air-water interface. Overall, thermostable conformational transition improved the interfacial activity of OVA and enhanced its foaming ability; however, overactive proteins were detrimental to the stabilization of its interfacial films.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier B.V. All rights reserved.)