Abstract: Fish scale storage methods affect the quality of fish scale gelatin. In this study, we investigated the effect of different fish scale storage methods (storage at room temperature, 4 and ?20 ℃ after sun drying, and storage at room temperature after hot air (60 ℃) drying) on gel strength, emulsifying activity and foaming ability of fish scale gelatin from bighead carp (Hypophthalmichthys nobilis). The structural characteristics of gelatins from fresh and stored fish scales were measured by Fourier transform infrared (FTIR) spectroscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and scanning electron microscope (SEM). Our results indicated that none of the storage methods for fish scales destroyed the characteristic molecular mass distribution (α chain, β chain and high molecular mass polymers) and FTIR peaks (amide A, amide I, amide II and amide III) of gelatin. All storage methods, especially 1 month storage at ?20 ℃, improved emulsifying activity and foaming ability of fish scale gelatin. All storage methods except 60 ℃ hot air drying could enhance gel strength, which may be related to the change of structural characteristics. Compared with fresh and hot air dried samples, sun drying and low temperature storage of fish scale increased the contents of α chain, β chain and high molecular mass polymers in fish scale gelatin, decreased the wavenumber of amide A, and made the network structure of gelatin gels more compact.

Key words: storage methods for fish scale, gelatin from bighead carp scale, gel strength, emulsifying activity, foaming ability, structural characteristics