冻结速率对鸡汤理化及流变特性的影响

摘要

The effects of different freezing rates on the physicochemical properties and rheological properties of chicken were studied,such as slow freezing at-20 ℃,rapid freezing at-40 ℃ and-80 ℃.The results showed that during freezing process,pH and soluble protein content were decreased,and conductivity,L* were increased.The conductivity,TBARS,soluble protein content of slow freezing group were significantly different from fresh chicken soup(p ＜ 0.05)and rapid freezing process(p ＜ 0.05).No significant physicochemical properties differences were found in-40 ℃ and-80 ℃frezzing(p ＞0.05) except conductivity.With the increase of shear rate,the viscosity value decreased and the shear stress increased.At the same shear rate,the viscosity and shear stress of the frozen chicken were lower than control group.The soup quality was significantly affected at-20 ℃ slow freezing.Compared with the slow freezing chicken,rapid freezing process has less effect on viscosity and shear stress.In conclusion,rapid freezing treatment will be more suitable to keep the quality of chicken soup.%以新鲜鸡汤为对照,探究不同冻结速率(-20、-40、-80℃冻结)对鸡汤理化性质和流变特性的影响.结果表明,-20℃鸡汤冻结组属于慢速冻结,-40、-80℃鸡汤冻结组属于快速冻结.冻结处理会使pH、可溶性蛋白含量降低,电导率、L*值增加.慢冻组的电导率、硫代巴比妥酸值(thiobarbituric acid reactive substances,TBARS)可溶性蛋白和速冻组的pH、可溶性蛋白均与新鲜鸡汤差异显著(p＜0.05).慢冻组与速冻组的电导率、TBARS差异显著(p＜0.05).速冻组-40℃和-80℃的鸡汤除了电导率,其他理化指标均无显著差异(p＜0.05).随剪切速率增加,鸡汤黏度值减小,剪切应力增大.剪切速率相同时,冻结组鸡汤表观黏度和剪切应力均低于对照组,-20℃慢速冻结对鸡汤流变影响较显著.速冻比慢冻对鸡汤溶液黏度、剪切力影响较小.综合分析,快速冻结更适合鸡汤冷冻处理.