Abstract
Samples frozen surimi (ground fishmeat) with different moisture and cod oil contents were subjected to measurements of fracture stress (bending fracture energy) in a low temperature range (below 0°C). The optimum conditions for low-temperature cutting (“cryo-cutting”) were estimated based on the enthalpy changes measured by a differential scanning calorimeter (DSC).
Frozen surimi samples with moisture contents of 60∼90% and containing 1∼20% cod oil, which had frozen at -40°C, could not be cut by bending, but they could be cut at -80°C (temperature A). The melting temperature of cod oil, as determined by DSC measurement, but they was above -80°C. Thus, the surimi could be cut below the melting temperature of cod oil as detected by DSC.
No significant decrease in the bending fracture energies of the surimi samples were measured below temperature A, and a glass transition was not observed on the DSC chart. It was considered that the presence of cod oil preverts glass transition in the surimi sample, because the melting temperature of cod oil overlaps with the glass transition range of surimi without oil.
The results showed that the optimum cutting temperature was below -80°C, and that it could be estimated by DSC measurement.
