Pea protein isolate-inulin conjugates prepared by pH-shift treatment and ultrasonic-enhanced glycosylation: Structural and functional properties

•A combined pH-shift/sonication treatment was used to promote the Maillard reaction.•The combined treatment reduced the particle size of pea protein isolates (PPI).•PPI-inulin conjugates were mainly connected by covalent and hydrogen bonds.•PPI-inulin conjugates had a high grafting degree and disordered secondary structure.•The combined treatment improved the solubility of PPI from pH 2 to 11. The application of pea proteins in the food industry is often limited by their poor functional properties, such as solubility, emulsification, and gelation. To address this problem, a novel method of constructing pea protein-inulin conjugates with improved functional attributes was developed, which consisted of combining a high-intensity ultrasonic treatment with a pH-shift wet heating method. This combined method promoted the Maillard reaction, leading to a grafting degree that was 2.3-times higher than that of the traditional wet heating method. SDS-PAGE confirmed the formation of pea protein-inulin conjugates. The pea protein-inulin conjugates had higher solubility than pea proteins alone, especially around the isoelectric point of the protein. Furthermore, the thermal stability, antioxidant activity, foaming and emulsifying properties of the conjugates were better than those of the protein. This study shows that the combined ultrasound/pH-shift wet heating method is highly effective at improving the functional properties of pea proteins.