Effect of Interaction Between Catechin and Glycosylated Porcine Hemoglobin on Its Structural and Functional Properties

Porcine hemoglobin (PHb) can endow and improve food quality during preparation, processing and storage. However, it is limited to be used in food because of its high viscosity, unstable properties and heavy blood smell, which people do not accept. Therefore, modification is important to improve its economic benefits and bioavailability. This study investigated the effect of the interaction between catechin and glycosylated porcine hemoglobin (G-PHb) on the functional characteristics and structure of the complex of catechin and glycosylated porcine hemoglobin (CG-PHb). PHb and G-PHb were used as controls. The solubility, turbidity, emulsifying property, surface hydrophobicity and oxidation resistance of CG-PHb were studied.The structural changes of the CG-PHb were analyzed via UV-Vis, FS, FT-IR and SEM. The results show that the solubility of CG-PHB increased significantly (p<0.05), and the turbidity decreased significantly (p<0.05). The emulsifying activity and stability were increased by 38.36%, 21.31%, 16.08% and 3.69% respectively (p<0.05), compared with the control group. CG-PHB has the largest surface hydrophobicity among the PHb, G-PHb and CG-PHB. When the concentration of the solution was increased to 1.60 g center dot mL(-1), the oxidation resistance was enhanced to 93.60%. Compared with the PHb and G-PHb, the UV absorption peak of CG-PHb has a wider peak shape, a larger peak and a slight red shift. The fluorescence peak intensity is CG-PHb>PHb>G-PHb. The secondary structure of CG-PHb was changed. Its beta-sheet content increased significantly (p<0.05), but the content of alpha-helix, beta-turn and irregular curl decreased (p<0.05). In addition, the scanning electron microscope showed that the protein structure changed due to the embedding of glycosyl groups and the interaction between glycosyl groups and catechins. It leads to the increase of the surface pore structure of CG-PHB. It is conducive to the exertion of its functional characteristics. This study can provide new ideas for protein modification research and provide a theoretical basis and reference for the property changes of the compound during food processing.