Structural modification of whey protein isolate via electrostatic complexation with Tremella polysaccharides and its effect on emulsion stability at pH 4.5

Yongqin Ma; Huixue Sun; Shanshan Zhang; Chenhe Yang; Elshan Musazade; Hongxiu Fan; Tingting Liu; Yanrong Zhang

doi:10.1016/j.ijbiomac.2025.139870

Structural modification of whey protein isolate via electrostatic complexation with Tremella polysaccharides and its effect on emulsion stability at pH 4.5

Int J Biol Macromol. 2025 Jan 13:297:139870. doi: 10.1016/j.ijbiomac.2025.139870. Online ahead of print.

Authors

Yongqin Ma¹, Huixue Sun¹, Shanshan Zhang¹, Chenhe Yang¹, Elshan Musazade², Hongxiu Fan¹, Tingting Liu¹, Yanrong Zhang³

Affiliations

¹ School of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; Scientific Research Base of Edible Mushroom Processing Technology Integration of Ministry of Agriculture and Rural Affairs, Changchun 130118, China.
² Key Laboratory of Soybean Molecular Design Breeding, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
³ School of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China; Scientific Research Base of Edible Mushroom Processing Technology Integration of Ministry of Agriculture and Rural Affairs, Changchun 130118, China; Engineering Research Center of Grain Deep-processing and High-efficiency Utilization of Jilin Province, Changchun 130118, China. Electronic address: zhangyanrong0044@jlau.edu.cn.

PMID: 39814289
DOI: 10.1016/j.ijbiomac.2025.139870

Abstract

Emulsions play an important role in food systems by encapsulating and delivering active compounds, but maintaining their stability under various conditions can be challenging. This study explored how the concentrations of Tremella polysaccharides (TPs) (0-0.75 %) affects the structural of whey protein isolate (WPI) and the stability of their emulsions at pH 4.5. At this pH, electrostatic interactions between WPI and TPs exposed hydrophobic groups within the protein, increased β-sheet contents, and improved the hydrophilic-hydrophobic balance, which enhanced emulsifying performance. WPI-TPs complexes (WTS) showed a high emulsifying activity index (57.85 m²/g) and emulsion stability index (82.03 %). Compared to WPI-only emulsions, WTS emulsions had smaller particle sizes, lower Turbiscan Stability Index (TSI) values, and higher viscoelasticity, thermal stability, freeze-thaw stability, and re-emulsification capacity. Importantly, when the TPs concentration in WTS emulsions exceeded 0.375 %, the TSI value dropped below 1, showing no particle migration or peak thickness, indicating full emulsion stability. These findings suggest that TPs help stabilize WPI emulsions near their isoelectric point (pH 4.5) and offer a promising approach to improving WPI functionality in acidic environments. The WTS system provides a reliable way to stabilize emulsions under acidic conditions, supporting the development of natural, stable emulsifiers for food applications.

Keywords: Acidic pH emulsification; Electrostatic complexes; Emulsion stability; Tremella polysaccharides; Whey protein isolate.