LWT-剑虾内源性酶的表征及其对冷冻储存期间肌肉蛋白质量的影响

浙江海洋大学食品与药学学院张宾教授团队在食品国际Top期刊LWT- Food Science and Technology上发表“Characterization of endogenous enzymes in sword prawn (Parapenaeopsis hardwickii) and their effects on the quality of muscle proteins during frozen storage”研究论文。

摘要：

由内源性酶引起的肌肉退化会大大影响虾类产品在加工和储存期间的质量。在这项研究中，研究了在120天的冷冻储存期间，完整的和被砍掉头的虾的胰蛋白酶、钙蛋白酶和组织蛋白酶活性的变化及其对肌肉蛋白质的影响。结果显示，随着储存时间的延长，完整和去头虾的硬度、拉伸力、咀嚼性、肌纤维蛋白（MP）含量和Ca2+-ATP酶活性都明显下降。值得注意的是，在整个冷冻储存期间，被砍头的虾比完整的虾样本表现出更稳定的特性。内源酶分析显示，与被砍头的样品相比，完整的虾的胰蛋白酶、钙蛋白酶和组织蛋白酶的活性变化明显。此外，肌纤维碎裂指数、SDS-PAGE和组织学结构分析显示，对虾的斩首处理大大抑制了冷冻储存期间肌肉蛋白的解离。我们的研究结果表明，在长期贮藏过程中，虾头部的胰蛋白酶可以通过第一腹节转移到肌肉组织中，从而加速了肌肉组织中MPs的降解。因此，斩首处理可以有效地延长了储存虾产品的保质期。

研究结果：

1. 质构分析

Data are represented as a mean ± standard deviation of three replicates. Different capital letters in the same column for the intact and beheaded shrimp samples on the same storage time indicated significant differences (t-test analysis; P < 0.05). Different lowercase letters in the same column for the hardness, stretching, adhesiveness, and chewiness of shrimp muscle during 120 days of storage indicated significant differences (one-way ANOVA analysis; P < 0.05).

2. MP含量和Ca2+-ATP酶活性分析

Fig. 1. Myofibrillar protein content (A) and Ca2+-ATPase activity (B) of the intact and beheaded shrimp samples during 120 days of frozen storage. Different lowercase letters indicate the significant differences (P < 0.05) between the intact and beheaded shrimp groups. Different uppercase letters in the same color for the same point plot indicate the significant differences (P < 0.05).

3. MFI分析

Fig. 2. MFI analysis of the intact and beheaded shrimp muscle during 120 days of frozen storage. Different lowercase letters indicate the significant differences (P < 0.05) between the intact and beheaded shrimp groups. Different uppercase letters in the same color for the same point plot indicate the significant differences (P < 0.05).

4. 胰蛋白酶活性分析

Fig. 3. Trypsin activity in the intact and beheaded shrimp samples during 120 days of frozen storage. Different lowercase letters indicated significant differences (P < 0.05) between the intact and beheaded shrimp groups. Different uppercase letters in the same color for the same point plot indicate the significant differences (P < 0.05).

5. 钙蛋白酶分析

Fig. 4. Calpain activity in the intact and beheaded shrimp muscle during 120 days of frozen storage. Different lowercase letters indicate the significant differences (P < 0.05) between the intact and beheaded shrimp groups. Different uppercase letters in the same color for the same point plot indicate the significant differences (P < 0.05).

6. 组织蛋白酶B、D、H和L活性分析

Fig. 5. Cathepsin B (A), D (B), H (C), and L (D) activity in the intact and beheaded shrimp muscle during 120 days of frozen storage. Different lowercase letters indicate the significant differences (P < 0.05) between the intact and beheaded shrimp groups. Different uppercase letters in the same color for the same point plot indicate the significant differences (P < 0.05).

7. 组织结构分析

Fig. 6. H&E staining micrographs of shrimp muscle tissues. A, Fresh shrimp; B and D, intact shrimp muscle stored after 60 days and 120 days, respectively; C and E, beheaded shrimp muscle stored after 60 days and 120 days, respectively.

8. SDS-PAGE分析

Fig. 7. SDS-PAGE analysis of shrimp muscle (total proteins). E, Fresh shrimp; A and C, beheaded shrimp muscle stored after 120 days and 60 days, respectively; B and D, intact shrimp muscle stored after 120 days and 60 days, respectively; M, molecular weight marker (11–245 kDa).

结论：

在这项工作中，测定了冷冻储存120天期间斩首剑虾的胰蛋白酶、钙蛋白酶、组织蛋白酶（包括B、D、H和L型）活性、MP含量、微观结构和质地特性，并与完整的虾样进行了比较。结果显示，在冷冻贮藏期间，去头虾和完整虾样品中提取的MPs和质地（包括硬度、拉伸力、粘附性和咀嚼性）明显下降。酶活性分析显示，在冷冻储存期间，完整的虾的胰蛋白酶、钙蛋白酶和组织蛋白酶活性的变化比斩首虾更不稳定。组织学分析显示，与完整的虾相比，被砍头的虾肌肉组织中的肌纤维之间存在很少的缝隙，这表明在冷冻储存期间，胰蛋白酶、钙蛋白酶和组织蛋白酶的释放可能会影响肌肉组织的微观结构。因此，斩首处理抑制了胰蛋白酶、钙蛋白酶和组织蛋白酶活性的增加，从而延长了储存虾产品的保质期。

原文链接：

https://doi.org/10.1016/j.lwt.2023.114563