Contribution of protein conformation and intermolecular bonds to fish and pork gelation properties

• Published in: Food hydrocolloids Vol. 25; no. 5; pp. 898 - 906
• Main Authors: Liu, Ru, Zhao, Si-Ming, Xie, Bi-Jun, Xiong, Shan-Bai
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.07.2011; Elsevier
• Subjects: Biological and medical sciences; Breaking; Conformation; cooked foods; cooking quality; Covalence; crosslinking; disulfide bonds; Fish; fish paste; Food additives; Food industries; Fundamental and applied biological sciences. Psychology; Gel property; Gelation; gels; General aspects; heat treatment; Heating; hydrogen bonding; Intermolecular bond; Meat and meat product industries; Pastes; Pork; protein conformation; Proteins; Raman spectroscopy; Spectra; spectral analysis; temperature; tyrosine; Gel property; Intermolecular bond; Raman spectroscopy; Heating; Conformation; Gelation; Meat product; Protein; Pork
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2010.08.016

Changes in protein conformation and intermolecular interactions during gelling were measured to explore the basis for the different gel properties of fish and pork pastes after heat treatment. Raman spectral analysis revealed that, in the unheated pork sample, more tyrosine residues were buried or involved as hydrogen bond donors than in the fish counterpart. Hydrophobic interaction increased and then decreased with increasing temperature, reaching a maximum value at 60 and 70 °C for fish and pork samples, respectively. Formation of disulfide bonds mainly occurred at 70–80 °C for fish, and 50–60 °C for pork samples. Incubation at 4–40 °C induced abundant non-disulfide covalent cross-linking in fish, but not in pork samples. The differences in protein conformation and intermolecular bonds possibly contributed to diverse gelation properties between fish and pork samples. At 40 and 50 °C, the breaking force of fish samples was significantly higher than that of pork. However, higher breaking force was observed in pork samples above 60 °C. Pre-incubation at 40 °C significantly increased the breaking force of the cooked fish sample, but had little effect on the breaking force of the cooked pork sample. In addition, incubating pork paste at 40 °C could decrease the cooking loss of the cooked pork sample. Fish and pork paste gels were produced by various heat treatments. Gelation properties were evaluated by textural analysis and measurement of cooking loss. Raman spectroscopy was employed to monitor the structural changes of proteins during gelling, and intermolecular bonding as a function of temperature was measured. Pre-incubation at 40 °C significantly increased the breaking force of the cooked fish sample, but had little effect on the breaking force of the cooked pork sample. In addition, incubating pork paste at 40 °C could decrease the cooking loss of the cooked pork sample. The differences were intimately associated with changes in protein conformation (α-helix and β-sheet) and intermolecular interactions (hydrophobic interaction, disulfide bonding and non-disulfide covalent crosslinking) during gelling.