罗非鱼片的肌肉分区特性及加工适性研究

Study on partitioning features and processing eligibility of muscle tissues of tilapia fillets

对罗非鱼片质构特性、冰点、蛋白质含量、粗脂肪含量、水分活度进行测定,按各部位差异性将鱼片分成背部外层、背部与中部、腹部、尾部4个肌肉类型区,并进一步测定各分区水分活度和TVB-N值的变化。结果表明:背部外层硬度、咀嚼性最大,弹性和凝聚性较小,蛋白质含量最低,水分活度最高,冰点最低;腹部弹性、凝聚性、咀嚼性最小,脂肪含量、水分活度最高,冰点略高于背部外层;背部与中部的弹性最大,蛋白质含量最高而脂肪含量、水分活度最低;尾部凝聚性和冰点最高。按分区分割的罗非鱼片在-20℃分别冷冻贮藏,各部位水分活度为背部外层>腹部>背部与中部>尾部;背部外层TVB-N值增加程度最大,腹部次之,背部、中部、尾部最小。

The parameters were measured, including textural proper- ties, freezing point; protein content, fat content and water activity on tilapia fillet＇s muscle tissue parts. According to the differences on these parameters, tilapia fillet was divided into four muscle areas and were outer back, back and middle, abdomen, tail. And further chan- ges in water activity and TVB-N value of each partition were meas ured. The results showed： the outer back displayed the highest hard hess and chewiness, small elasticity and cohesion, the lowest protein content, a slightly higher fat content, the maximum water activity, and the lowest freezing point. The elasticity, cohesiveness, chewi- ness on abdomen were the minimum, while the fat content, water activity were the highest; the freezing point on abdomen was slightly higher than the outer back. The part of back and middle displayed the highest elasticity and protein content, the lowest fat content and water activity, and a freezing point below the abdomen and above the tail. The tail displayed the largest cohesion and freezing point. The water activity in the various parts of frozen tilapia muscle tissue which were stored at -20 ℃ respectively, after being divided, was reduced in the order of outer back〉abdomen〉back and middle〉 tail. The TVB-N values＇ change in outer back displayed the highest increases, in the abdomen it had a lesser increase, while in the back, middle and tail it displayed a reduce to the minimum extent.