Thermophysical Properties and Tempering Rate of Tuna Under Different Brining Conditions
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.
salt concentrationsrefrigerated temperingradio frequency temperingthawing rateuniformity