Abstract:The value-added utilization of rice dreg protein and the development of plant-based foaming agents were explored.Rice dreg protein was used as the raw material for comparison of the effects of pH-shift alkaline hydrolysis，pH-shift acid hydrolysis，and enzymatic hydrolysis on the protein foaming properties，and the corresponding modification mechanisms were elucidated.Single-factor experiments were conducted to optimize the process conditions for each of the three methods.The results showed that pH-shift alkaline hydrolysis（at 80 ℃ for 3 h，pH10）significantly improved the foaming capacity and foam stability of rice dreg protein（reaching 300% and 73%，respectively），outperforming both enzymatic hydrolysis and pH-shift acid hydrolysis.Structural characterization revealed that the modified protein exhibited a reduced particle size，altered molecular weight distribution，a rearranged secondary structure（increased α-helix and random coil content），and decreased surface hydrophobicity.Additionally，the cross-linking effect of calcium ions during pH-shift alkaline hydrolysis contributed to the formation of a stable foam structure.