Abstract:The pH of porcine plasma protein (PPP)-xanthan gum (XG) composite solution was adjusted to 3.5 using gluconolactone (GDL) as an acidifying agent, resulting in the formation of stable PPP-XG composite gels. The results of textural, rheological, and electron microscopic analyses showed that even low concentrations of PPP and XG could form typical gels with dense network structures. The Zeta potential and interaction force studies demonstrated that non-covalent interactions occurred between PPP and XG, with electrostatic and hydrogen bonding as the primary driving force. Under specific mass fraction of polysaccharide, the gel had the maximum hardness at a protein-to-polysaccharide ratio of 1:1. However, under other conditions, the gel hardness showed a decreasing trend. XG had a promoting effect on the gel hardness. When the mass fraction of XG was 0.3%, the mixed solution had appropriate viscosity and hardness. The gel with a PPP mass fraction of 0.3% had the maximum hardness of 250.02 g, with the lowest water retention capacity of 53.96%, highest synergistic value of 9.77%, and strongest energy storage modulus and intermolecular forces, resulting in a dense gel structure. The swelling property measurement showed that the water absorption capacity of the composite gel at a pH value of 7.4 was significantly higher than that at a pH of 2.0 (P<0.05). This study indicated that the composite gel could improve the texture characteristics of food products and serve as a delivery vehicle for thermosensitive ingredients, providing valuable insights for food processing.
