脆肉鲩低温相变区热特性的研究

Thermo-physical Properties of Crisped Grass Crap Meat during Low Temperature Phase Transition

采用差示扫描量热仪,研究脆肉鲩鱼肉在低温相变区的冰点、表观比热和热焓以及NaCl、NaCl与蔗糖混合物添加量对脆肉鲩热特性的影响。结果表明,脆肉鲩鱼肉的冻结相变温区为-12.5～-11℃,熔融相变温区为-1.9～0.1℃,冰点为-0.2℃,冰点的表观比热和热焓值分别为130.56J/g·℃、305.57J/g。随着NaCl、NaCl和蔗糖混合物添加量的增加,脆肉鲩肌肉的相变温区向低温方向移动,冰点的表观比热和热焓值下降。鱼肉中NaCl添加量较低时,添加蔗糖可减缓相变温度的下降,当NaCl添加量大于2%时,添加蔗糖对鱼肉相变区温度的影响不大,NaCl起主导作用。

In order to provide theoretical supports for storage process of crisped grass crap meat, effects of NaCl and sucrose-NaCl mixture on thermo-physical properties including freezing point, apparent specific heat, and enthalpy of crisped grass crap meat were determined by differential scanning calorimetry （DSC） at low temperature phase transition area. The freezing phase transition range, thawing phase transition range, freezing point, apparent specific heat, enthalpy at freezing point of crisped grass crap meat were-12.5--11℃, -1.9-0.1 ℃,-0.2 ℃, 130.56 J/g·℃, and 305.57 J/g, respectively. As the content increase of NaCl and sucrose-NaCl mixture, phase-transition temperature shifted to the lower temperature range and both apparent specific heat and enthalpy at freezing point decreased. When NaCl content in meat was low, addition of sucrose could depress the drop of phase-transition temperature. In contrast, when NaCl content was higher than 2%, sucrose had little effect and NaCl exhibited the leading role during low temperature phase transition.