Abstract:
The effects of freeze-drying and flake freezing of surimi on biochemical and
physical properties as affected by various storage conditions were examined. Using
three cooking parameters shear stress and strain values were evaluated to measure
gelation properties of surimi gels. Stress values increased up to 3 months and then
decreased substantially as storage time was extended. In general, strain values
decreased substantially over time, however, freeze-dried surimi kept in the freezer at -
18°C did not change during 9 months of storage. Overall, color decreased during
storage and b* values of the freeze-dried surimi kept at room temperature increased
significantly. Salt extractable proteins decreased while dimethylamine increased.
Electrophoretic patterns, however, did not show any apparent damage to the MHC due
to frozen storage and/or proteolysis (with 60°C incubation) until the 9th month of storage.
At 9 months, a reduction of the MHC was observed and the lower molecular weight
bands were more intense. Freeze-dried samples stored in the freezer maintained the highest quality for the duration of the 9 month study. Low temperature storage is
important for retaining good functionality in freeze-dried surimi.
The effects of cross-section diameter on shear stress and strain and effects of
individual variation in measuring diameter were studied. Gelation properties of surimi
using milled and molded gels were compared. The possibility of skin formation using
various cook times was also evaluated. Shear stress values were significantly affected
by diameter accuracy, whereas the effect was not as significant for shear strain values.
Individual variation in measurement was also greatly noted. Molded gels resulted in
significantly lower strain values than milled samples, whereas stress values were
significantly higher in molded gels than in milled gels. Using a lechitin-based spray
appeared to eliminate skin formation on all samples.
