不同腌渍条件下金枪鱼肉的热物性及解冻速率研究

Thermophysical Properties and Tempering Rate of Tuna Under Different Brining Conditions

腌渍对延长水产品保质期和保持其品质具有重要意义,腌渍后水产品的冷冻后解冻工艺需根据原料热物性变化进行探索。以黄鳍金枪鱼为研究对象,将鱼片在质量体积分数为0.00%(对照)、1.44%、2.88%、5.75%与11.50%的NaCl水溶液中腌渍2 h,测定其不同温度下的密度、比热容、热导率与介电特性,并分别进行冷藏解冻与射频解冻。结果表明:随着盐水中NaCl质量体积分数增大,鱼肉密度先减后增,比热容和热导率逐渐降低,介电常数与介电损耗均逐渐升高;腌渍后金枪鱼的冷藏解冻与射频解冻的速率均随NaCl水平增加而降低,射频解冻速率远高于冷藏解冻;冷藏解冻的均匀性优于射频解冻,而射频解冻均匀性随NaCl水平升高有所改善。研究结果为腌渍金枪鱼的射频解冻工艺探索打下了基础,未来可进一步改善均匀性以提高解冻品质。

Brining is of great significant for extending the shelf life and maintaining the quality of aquatic products,but the freezing and thawing process of brined aquatic products needs to be explored based on changes in the thermal properties of the raw materials.Yellow-fin tuna slices were immersed in NaCl solutions with mass volume fractions of 0.00%(CK),1.44%,2.88%,5.75%,and 11.50% for a duration of 2 h to study the effects of brining on the density,specific heat capacity under different temperatures,and refrigerated tempering and radio frequency(RF)tempering were used to thaw brined tuna.Additionally,both conventional refrigerated and radio frequency(RF)tempering methods were employed.The results showed that with the mass fraction of salt in the brine solution increasing,the density of the fish firstly decreased and then increased,while specific heat capacity and thermal conductivity gradually decreased,and the dielectric constant and dielectric loss factor increased progressively.The tempering rates of both refrigerated and RF tempering decreased with the increasing of salt levels in the brine solution,with RF tempering significantly outpacing refrigerated tempering in terms of speed.Refrigerated brining exhibited superior uniformity compared to RF tempering,although the uniformity of RF tempering improved as the salt level in the brine solution increased.These findings laid foundation for exploring RF tempering processes of brined yellow-fin tuna,and was helpful for improving uniformity and enhancing tempering quality in further.