Structural properties of aggregates from frozen stored hake muscle proteins

Raman spectroscopy and electron microscopy were used to examine the structural properties of sodium dodecyl sulfate-mercaptoethanol-unextractable aggregates formed during the frozen storage of hake muscle. Our results showed that: (a) the unextractable residue consisted of thick filaments, which appeared connected and aggregated, forming a network; (b) the protein backbone adopted a conformational structure rich in β-sheets; and (c) Raman spectroscopy revealed for the 1st time the presence of symmetrical stretching vCH2 bands, whose frequencies are consistent with the presence of lysine-arginine and/or lysine-glutamine/asparagine bridges in the aggregates.Peer Reviewe