TitleRaman spectroscopy determines structural changes associated with gelation properties of fish proteins recovered at alkaline pH.
Publication TypeJournal Article
Year of Publication2006
AuthorsThawornchinsombut, S, Park, JW, Meng, G, C Y Li-Chan, E
JournalJ Agric Food Chem
Volume54
Issue6
Pagination2178-87
Date Published2006 Mar 22
ISSN0021-8561
KeywordsAnimals, Cryoprotective Agents, Fish Proteins, Fishes, Food Preservation, Freezing, Gels, Hydrogen-Ion Concentration, Microscopy, Electron, Scanning, Protein Structure, Secondary, Seafood, Spectrum Analysis, Raman
Abstract

Structural changes of alkali-treated rockfish protein isolate (AKPI) during frozen storage were elucidated using a Raman spectrometer and scanning electron microscope (SEM). The results were compared to conventional surimi (CS). No significant textural difference was noted between AKPI stored at pH 5.5 and 7.0. The strongest texture was found for AKPI frozen with cryoprotectants and CS, while the weakest texture was observed in AKPI frozen without cryoprotectants. SEM revealed the most discontinuity in gels of AKPI with no cryoprotectants and a more aggregated microstructure after storage at pH 5.5 than at neutral pH. Raman spectral analysis demonstrated refolding of AKPI by pH readjustment to 7.0, although the refolded structure was not identical to that before the pH shift. CS showed higher alpha-helix content (approximately 50%) than AKPI (approximately 20-30%). Frozen storage induced a decrease and an increase in the alpha-helix content of CS and AKPI samples, respectively. AKPIs were slightly less stable than CS during frozen storage.

DOI10.1021/jf0518958
Alternate JournalJ. Agric. Food Chem.
PubMed ID16536593