Preparation, Characterization, and Umami Enhancement Properties of Maillard Peptides from Zanthoxylum Seed Protein

To enhance the high-value utilization of Zanthoxylum seeds and develop novel Zanthoxylum-based specialized seasonings, this study utilized Zanthoxylum seed protein as the raw material, subjecting it to sequential enzymatic hydrolysis with alkaline protease and flavor protease, followed by the Maillard reaction to synthesize umami peptides. The Maillard peptide preparation process was optimized by single-factor experiments and response surface methodology with browning degree and sensory evaluation as indicators. The effects of Maillard reaction on the flavor characteristics of Zanthoxylum seed protein hydrolysates were investigated using an electronic tongue in combination with the analysis of molecular weight distribution, amino acid content, peptide sequence, and other characteristic indicators. The results indicated that the optimal conditions for preparing Zanthoxylum seed protein Maillard peptides were as follows: Protein-to-sugar ratio of 3:2 (g/g), reaction temperature of 106 ℃, and reaction time of 52 min. Under these conditions, the product exhibited an electronic tongue response value of 10.06 and a sensory evaluation score of 8.38. The umami-enhancing effect was statistically significant (P<0.01), achieving an effective 44% reduction in monosodium glutamate content. Following the Maillard reaction, the proportion of peptides within the 500~1000 Da molecular weight range increased from 6.14% to 14.88%, while the content of umami amino acids increased by 8.95% and the content of bitter amino acids decreased by 5.31%. These results suggest that the Maillard reaction effectively enhances the umami taste of Zanthoxylum seed protein peptides and enriches their flavor complexity. This study provides important theoretical support for the development of novel seasonings that can replace sodium salts.