凡纳滨对虾肌肉蛋白质的热变性及其对品质的影响

Effect of the Thermal Denaturation of Litopenaeus Vannamei Muscle Protein on the Quality Characteristics during Heat Processing

以凡纳滨对虾为对象,利用拉曼光谱技术研究加热过程中肌肉蛋白二级结构变化对品质特征的影响。研究结果表明:在加热过程中凡纳滨对虾二级结构发生了较大变化,导致质构特性及失水率发生相应的变化。在加热初始阶段30s时,凡纳滨对虾虾肉失水率为0.72%。随着加热时间的延长,失水率快速增加,10 min时达14.8%;同时虾肉质构指标也发生明显变化,即:硬度由初始的991.7848 N增至2 167.7830 N,最后降至1 768.9260 N;弹性由1.1805增至1.3131,再减至1.3088;黏性由7.6197 Pa·s减至1.6068 Pa·s,又增至3.2155 Pa·s;而内聚性、胶黏性、回复性、耐咀性均呈先生高后略微降低的趋势。这可能与虾肉蛋白加热过程中二级结构发生构象变化密切相关,其中α螺旋由新鲜的23.14%降至18.64%,β-折叠含量由23.91%升至29.51%,无规卷曲结构由31.80%升至33.91%。

Raman spectroscopy was applied for studying the protein secondary structure of leg shrimp（Litopenaeus vannamei） affecting quality characteristics during heating process. Results showed that along with the heating time extension, secondary structure changed a lot, leading to texture characteristics and water loss rate changed correspondingly. At the initial heating stage, water loss rate of sample（30s） was 0.72%. Along with the heating time extension, water loss rate increased rapidly, reached 14.8%. In addition, texture characteristics of leg shrimp also had obvious changes. Hardness increased from 991.7848 N to 2167.7830 N, and then reduced to 1768.9260 N; elasticity increased from 1.1805 to1.3131, and then reduced to1.3088; viscosity reduced from 7.6197 NS to 1.6068 NS, and then increased to 3.2155 NS.Cohesiveness, tackiness, recoverability, chewiness increased and then slightly reduced, respectively. It＇s because of conformation change of meat during heating, α-helix varied from 23.14% to 18.64%, β-sheet changed from 23.91% to 29.51%, random coil varied from 31.80% to 33.91%.