不同冻结温度对牛肉营养品质的影响
毕业论文关键词：冻结温度；解冻方法；牛肉品质。
Effects of different freezing temperatures on the quality of beef
Abstract: This test was carried out on several aspects of the experiment on the influence of different freezing methods for beef quality and subject, mainly discusses the effect of freezing loss, cooking loss, texture, lipid oxidation, amino acid content, the microstructure of beef juice. The results showed that the sap loss rate and cooking loss rate of beef under freezing temperature -23℃were lower than -18℃ and -13℃, and the lower the freezing temperature, the better the water holding capacity of beef. The texture of frozen beef was significantly different from that of fresh sample in terms of hardness and chewiness. The meat hardness and chewiness increased after freezing treatment. The higher the freezing temperature, the greater the hardness and chewiness. The cohesion and elasticity of meat processed by freezing decreased gradually, but the difference was not significant. The influence of freezing method on the degree of lipid oxidation was not significant. The amino acid concentration of frozen beef was higher than that of the control group. However, the influence of different freezing methods on the content of amino acids in beef was not significant. With the increase of freezing temperature, the destruction degree of muscle fiber increases.
Key words: Freezing temperature; thawing method; beef quality.
目 录
摘要3
关键词3
Abstract3
Key words3
引言3
1材料与方法4
1.1材料和仪器 4
1.1.1试验材料及处理方法4
1.1.2 试验仪器与试剂4
1.2 方法4
1.2.1冻结方法4
1.2.2解冻方法4
1.2.3指标测定4
1.3.1汁液流失率4
1.3.2蒸煮损失率 4
1.3.3质构测定5
1.3.4脂肪氧化5
1.3.5氨基酸测定5
1.3.6微观结构观察5
1.3.7数据处理5
2结果与分析5
2.1不同冻结方式对牛肉解冻汁液流失率的影响5
2.2不同冻结方式对牛肉蒸煮损失率的影响6
2.3不同冻结方式对牛肉质构的影响6
2.4脂肪氧化7
2.5氨基酸变化7
2.6微观结构观察8
3讨论9
致谢9
参考文献10
不同冻结温度对牛肉营养品质的影响
引言：
冷冻是贮藏原料肉最方便、有效的方法之一。冷冻技术对肉的最终品质有很大的影响。冻藏食品中冰晶大小、分布直接影响随后的解冻过程渗出物的多少和最终食品的质量[1,2]。FDA推荐肉制品应在冷藏或低于5℃条件下进行解冻[3]。加拿大食品监督局建议消费者在室温下解冻超过2h的食品将不能再食用[4]。Sanza[5]研究表明,冷冻保藏食品会因大块冰晶的形成,不仅可以破坏细胞膜、损伤组织结构,而且会引起蛋白质的变性,同时冰晶的大小和分布的不同会使食品在解冻时汁液流出,最终影响食品的质量,如风的下降、汁液的流失、酸败、冰结晶的升华和重结晶、脱水、嫩度下降、可溶性蛋白质的含量减少、蛋白质的凝胶形成能力下降等,这些变化当中蛋白质的冻结变性会对肌肉质地有很大的影响。在实际生产过程中影响肌肉质量损失情况的因素有很多,如冻结、解冻的速率,冻藏的温度,冻藏过程中温度的波动,反复的冻融等等。因此，选择合适的冻结方式和改善措施十分重要。
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