冻融次数对藏羊肉品质特性的影响

为研究反复冻融次数对冷藏藏羊肉品质特性的影响。本文以欧拉藏羊肉为研究对象，经反复冻融0、1、3、5次后置于4 ℃条件下冷藏1、3、5、7 d，测定其营养品质、食用品质、质构以及脂质氧化程度。研究结果显示，随着冻融次数的增加，藏羊肉营养品质明显降低，表现为水分含量和蛋白质含量显著下降（P < 0.05）；藏羊肉食用品质整体呈显著下降变化，尤其在冻融循环5次后，肉色稳定性及保水性均呈显著下降变化（P < 0.05），嫩度略有下降但变化不大，且肌肉硬度及咀嚼性整体呈下降变化，黏度、弹性和胶着性均呈上升变化；过氧化值（POV）和硫代巴比妥酸值（TBARS）均在冻融循环5次后达到最大值（P < 0.05），说明脂肪氧化程度随冻融次数增加而加重；同时，冷藏时间的延长也会进一步加剧肌肉品质的劣变，且冻融循环次数越多劣变越严重。可见，冻融循环次数的增多对肌肉品质有较大影响，在肉类实际生产加工和运输过程中应尽量避免反复冻融现象的发生。

Effect of Freezing-Thawing Times on Quality Characteristics of Tibetan Mutton

In order to study the effects of freezing-thawing times on the quality characteristics of frozen mutton. After freezing and thawing repeatedly for 0, 1, 3, 5 times and then refrigerated at 4 ℃ for 1, 3, 5, 7 days, the nutritional quality, edible quality, texture characteristics and lipid oxidation degree of Oula Tibetan mutton were determined. The results showed that with the increase of freeze-thaw times, the nutritional quality of Tibetan mutton deteriorated significantly, the moisture content and protein content decreased significantly (P < 0.05); The overall eating quality of Tibetan mutton decreased significantly, especially after 5 freeze-thaw cycles, the color stability and water holding capacity decreased significantly (P < 0.05), the tenderness decreased slightly, but the change was not significant, and the meat hardness and chewiness decreased, while the viscosity, elasticity and adhesiveness increased; Meanwhile, peroxide value (POV) and thiobarbituric acid value (TBARS) reached the maximum after 5 freeze-thaw cycles (P < 0.05), indicating that the degree of lipid oxidation increased with the increase of freeze-thaw cycles; At the same time, the longer the cold storage time, the worse the meat quality. The above results showed that the increase of freeze-thaw cycles had a great impact on the meat quality, and the repeated freeze-thaw phenomenon should be avoided in the actual production, processing and transportation of meat.