engleski

EFFECT OF k-CARRAGEENAN AND NaCl ON THERMAL PROPERTIES OF FROZEN SURIMI PREPARED FROM ADRIATIC PILCHARD

Samples of surimi were prepared in laboratory conditions from Adriatic pilchard (Sardina pilchardus). Water content in surimi was 81.5% before mixing with NaCl and k-carrageenan, which were added in the range of mass fraction from 0 to 10%. Relative apparent specific enthalpy H, initial freezing point Ti, density ro, and thermal conductivity k of surimi in the temperature range from -25 oC to 10 oC were determined by: differential thermal analysis (DTA), gravimetric method and the line heat source technique. For determination of relative apparent specific enthalpy the mathematical model of enthalpy based on orthogonal collocation approximation of DTA was applied. Redistributions of apparent enthalpy in the freezing range as functions of mass fractions of added substances were determined. Increase of mass fraction of added substances resulted in increase of mass fraction of bound (unfreezable) water and lowered initial freezing point Ti, which has effects on decrease of thermal conductivity k and increase of apparent specific enthalpy in the temperature range from -25 oC to Ti. This effect was more pronounced for samples where surimi was mixed with NaCl.

thermal properties; frozen surimi; k-carrageenan; NaCl

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