Effect of acid/alkali shifting on function, gelation properties, and microstructure of Mesona chinensis polysaccharide-whey protein isolate gels

This paper investigates the potential of composite gels, formed by the pH-treated whey protein isolation (WPI) and Mesona chinensis polysaccharides (MCP) solutions, as jelly processing ingredients. The functional, gelation properties, and microstructure of MCP-WPI gels were investigated under specific conditions (pH 4?10). The results showed that MCP and WPI can form a stable gel under the condition of pH 10, ?-potential increased and the particle size decreased with the increase of pH. The water-holding capacity (WHC) of MCP-WPI gels was the lowest at pH 6 and the highest at pH 10. Rheological results showed that the apparent viscosity, storage modulus (G?), and loss modulus (G?) of MCP-WPI gels increased with the increase of pH. At pH 10, MCP-WPI gels had the highest creep/recovery ability. The gel strength and rupture stress of MCP-WPI gels increased significantly (P < 0.05) with the pH. The more uniform structure and finer water pores were observed with scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) in higher pH conditions (pH 8 and 10), and more disordered and coarse gel networks were formed at pH 4 and pH 6. These results indicated that higher pH promoted MCP-WPI gel formation, which provided a reference for the innovation of heat-induced gel material in the medical and food industries.