Maillard reacted wheat gluten and polydextrose complex enhances the emulsifying properties and stability of pickering emulsion

This study aims to explore the characteristics and stability of Pickering emulsion based on the Maillard reaction products of polydextrose (PDX) and gluten. The effects of the PDX:gluten ratio (from 0.0:1 P_0.0G₁ to 2.4:1 P_2.4G₁) during Maillard reaction on Pickering emulsion quality were examined. The degree of PDX grafting to gluten increased from 0.51% ± 0.05%–18.99% ± 0.98% when the PDX:gluten ratio increased from 0.2:1 to 2.2:1. Scanning electron microscopy and infrared spectroscopy confirmed the structural change and covalent interaction of PDX–gluten conjugate. The P_2.2G₁ conjugate showed a higher emulsification activity (1.82 ± 0.04 m²/g) compared with P_0.0G₁ (0.97 ± 0.05 m²/g). The particle size, ζ-potential value and confocal laser scanning microscopic image of PDX–gluten conjugate-based emulsion were compared with those of gluten-based emulsion to illustrate the stability role of PDX–gluten conjugate in the interfacial layer of Pickering emulsion. This study demonstrated that the Maillard reacted gluten–PDX conjugate was a potential stabilizer for Pickering emulsions. These findings provided a foundation knowledge for the construction of Pickering emulsion based on PDX–gluten conjugates.