Insights into the effect and mechanism of low-bitterness porcine hemoglobin hydrolysates produced by γ-glutamyl transpeptidase.

While the potential of γ-glutamyl transpeptidase from Bacillus amyloliquefaciens for reducing bitterness in porcine hemoglobin hydrolysates has been demonstrated, the underlying mechanistic basis remains unexplored. In the present study, 6 h γ-glutamyl transpeptidase treatment was demonstrated to significantly decrease bitterness intensity (P < 0.05), while enhancing umami characteristics in hemoglobin hydrolysates. The enhanced taste profile of hemoglobin hydrolysates was primarily attributed to the formation of γ-glutamyl peptides. Eighteen γ-glutamyl peptides, four bitter peptides, and four umami peptides were identified by UPLC-MS/MS. The highest CDOCKER score was -448.238 kcal/mol for γ-Glu-Leu-Arg-Glu, indicating a strong affinity with calcium-sensing receptor. Sensory evaluation further revealed that γ-Glu-Leu-Arg-Glu's synergistically suppressed the bitter taste, reducing the bitterness score of Val-Val-Tyr-Pro-Trp-Thr-Gln-Arg-Phe from 4.36 to 3.36 (P < 0.05) in the presence of His-Leu-Gln-Leu-Ala-Ile-Arg. These findings provide a theoretical foundation for reducing bitterness in blood by-products, thereby supporting their high-value utilization.