关键词: 麻鸭, 肌原纤维蛋白, 二级结构, 热诱导凝胶, 拉曼光谱

Abstract: In order to investigate the effect of heating temperature (50–100 ℃) on myofibrillar protein (MP) structure and gel properties of sheldrake breast muscle, water-holding capacity (WHC), texture, surface hydrophobicity, microstructure and secondary structure were determined. Correlation analysis was performed to establish relationships among heating temperature, protein structure and gel properties. Results showed that the lowest WHC was obtained by heating at 50 ℃, heating at 60 ℃ could result in MP denaturation and aggregation, and a compact and exquisite gel structure was formed at 70 ℃. As the heating temperature increased, the pore size of the gel network became larger and the WHC decreased significantly (P < 0.05). The normalized strength of the characteristic absorption peaks at 545, 760 and 1 340 cm-1 in the Raman spectral showed a downward trend with increasing heating temperature, indicating changes in the disulfide stretching vibration together with gradual exposure of buried tryptophan residues and increased surface hydrophobicity. The α-helix content decreased significantly (P < 0.05) from 66.95% to 19.73% when the heating temperature increased from 50 to 100 ℃, while the contents of β-sheet, β-turn, and random coil increased. In summary, a homogeneous sheldrake MP gel microstructure was formed by heating at 70 ℃ and the formed gel had the maximum WHC .

Key words: sheldrake, myofibrillar protein, secondary structure, heat-induced gelation, Raman spectroscopy