Dynamic changes in the aggregation-depolymerization behavior of Ovomucin-Complex and its binding to urease during in vitro simulated gastric digestion

Yanqing Wan; Zhiman Xu; Shengnan Zhu; Yuan Zhou; Xin Lü; Yuanyuan Shan

doi:10.1016/j.ijbiomac.2024.132295

Dynamic changes in the aggregation-depolymerization behavior of Ovomucin-Complex and its binding to urease during in vitro simulated gastric digestion

Int J Biol Macromol. 2024 May 10;270(Pt 1):132295. doi: 10.1016/j.ijbiomac.2024.132295. Online ahead of print.

Authors

Yanqing Wan¹, Zhiman Xu¹, Shengnan Zhu¹, Yuan Zhou¹, Xin Lü¹, Yuanyuan Shan²

Affiliations

¹ College of Food Science and Engineering, Northwest A&F University, Yangling, PR China.
² College of Food Science and Engineering, Northwest A&F University, Yangling, PR China. Electronic address: shanyuanyuan@nwafu.edu.cn.

PMID: 38735615
DOI: 10.1016/j.ijbiomac.2024.132295

Abstract

Ovomucin-Complex extracted from egg white is expected to have a barrier function similar to gastric mucin. In this study, the dynamic changes in structure, rheological properties and binding ability of Ovomucin-Complex during in vitro simulated gastric digestion were investigated. The results from HPLC and CLSM showed that extremely acidic pH (pH = 2.0) promoted Ovomucin-Complex to form aggregation. Acid-induced aggregation may hinder its binding to pepsin, thus rendering Ovomucin-Complex resistant to pepsin. Consequently, most of the polymer structure and weak gel properties of Ovomucin-Complex retained after simulated gastric digestion as verified by HPLC, CLSM and rheological measurement, although there was a small breakdown of the glycosidic bond as confirmed by the increased content of reducing sugar. The significantly reduced hydrophobic interactions of Ovomucin-Complex were observed under extremely acidic conditions and simulated gastric digestion compared with the native. Noticeably, the undigested Ovomucin-Complex after simulated gastric digestion showed a higher affinity (K_D = 5.0 ± 3.2 nm) for urease - the key surface antigen of Helicobacter pylori. The interaction mechanism between Ovomucin-Complex and urease during gastric digestion deserves further studies. This finding provides a new insight to develop an artificial physical mucus barrier to reduce Helicobacter pylori infection.

Keywords: In vitro simulated gastric digestion; Ovomucin-Complex; Rheological properties.