High‐Value Utilization of Porcine Blood Byproducts: Structural, Functional, and Kinetic Insights Into EGCG and Nitrosylation Dual Modification of Porcine Hemoglobin

ABSTRACT

Livestock blood is a protein‐rich byproduct with considerable potential for valorization, but its utilization remains limited. In this study, an Epigallocatechin gallate (EGCG)‐nitrosylated porcine hemoglobin complex (EN‐PHb) was constructed through a chemical‐polyphenol dual‐modification strategy to improve the functional properties of porcine hemoglobin (PHb). Multi‐spectroscopic analyses demonstrated that EGCG binding to nitrosylated porcine hemoglobin (N‐PHb) induced conformational rearrangement, characterized by increased β‐sheet content and alterations in the protein microenvironment. Two‐dimensional correlation spectroscopy revealed the sequential structural responses during complex formation, indicating that EGCG‐mediated interactions initially affected the amide II region, followed by coordinated changes in the peptide backbone and hydrophobic side‐chain microenvironment. Molecular docking and molecular dynamics simulations further demonstrated that EGCG interacted with N‐PHb through hydrogen bonding, van der Waals forces, and hydrophobic interactions, with a binding free energy of −22.06 kJ mol ⁻¹ . Differential scanning calorimetry showed that EGCG incorporation enhanced the thermal stability of N‐PHb, increasing its denaturation temperature from 93.37°C to 100.49°C. These structural modifications further endowed EN‐PHb with improved functional properties, including enhanced solubility, emulsifying performance, and free radical scavenging capacity. This study provides an effective strategy for the functional modification and processing utilization of PHb, offering theoretical support for the high‐value development of livestock blood‐derived protein resources.