Raman spectroscopy determines structural changes associated with gelation properties of fish proteins recovered at alkaline pH

Supawan Thawornchinsombut, Jae W. Park, Guangtao Meng, Eunice C Y Li-Chan

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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 α-helix content (∼50%) than AKPI (∼20-30%). Frozen storage induced a decrease and an increase in the α-helix content of CS and AKPI samples, respectively. AKPIs were slightly less stable than CS during frozen storage.

Original languageEnglish
Pages (from-to)2178-2187
Number of pages10
JournalJournal of Agricultural and Food Chemistry
Issue number6
Publication statusPublished - 2006 Mar 22
Externally publishedYes


ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Food Science
  • Chemistry (miscellaneous)

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