Key Laboratory of Key Technical Factors in Zhejiang Seafood Health Hazards, Institute of Innovation & Application, Zhejiang Ocean University, Zhoushan 316022, China.
Rizhao Agricultural Products Quality and Safety Inspection and Testing Center, Rizhao 276800, China.
Molecules. 2022 Apr 26;27(9):2771. doi: 10.3390/molecules27092771.
Defatted Antarctic krill powder is the main by-product in the manufacturing of krill oil. Exploring a high value-added approach for utilizing this protein-rich material has received much attention in research and industry. Given this, the preparation and primary characterization of antifreeze peptides from defatted Antarctic krill (AKAPs) were carried out in this study. The cryoprotective effect of AKAPs on Lactobacillus rhamnosus ATCC7469 was also investigated. The results showed that Protamex was the optimum protease for AKAP preparation from defatted Antarctic krill. AKAPs were found to be rich in short peptides, with the MW ranging from 600 to 2000 Da (69.2%). An amino acid composition analysis showed that AKAPs were rich in glutamic acid (18.71%), aspartic acid (12.19%), leucine (7.87%), and lysine (7.61%). After freezing, the relative survival rate of Lactobacillus rhamnosus in the 1.0 mg/mL AKAP-treated group (96.83%) was significantly higher than in the saline group (24.12%) (p < 0.05). AKAPs also retarded the loss of acidifying activity of L. rhamnosus after freezing. AKAPs showed even better cryoprotective activity than three commercial cryoprotectants (sucrose, skim milk, and glycerol). In addition, AKAPs significantly alleviated the decrease in β-galactosidase and lactic dehydrogenase activities of L. rhamnosus (p < 0.05). Furthermore, AKAPs effectively protected the integrity of L. rhamnosus cell membranes from freezing damage and alleviated the leakage of intracellular substances. These findings demonstrate that AKAPs can be a potential cryoprotectant for preserving L. rhamnosus, providing a new way to use defatted Antarctic krill.
脱脂南极磷虾粉是磷虾油生产的主要副产物。探索利用这种富含蛋白质的材料的高附加值方法，在研究和工业界引起了广泛关注。鉴于此，本研究进行了从脱脂南极磷虾（AKAPs）中制备和初步表征抗冻肽的研究，并考察了 AKAPs 对鼠李糖乳杆菌 ATCC7469 的冷冻保护作用。结果表明，Protamex 是从脱脂南极磷虾制备 AKAP 的最佳蛋白酶。AKAPs 富含短肽，MW 分布在 600 至 2000 Da（69.2%）之间。氨基酸组成分析表明，AKAPs 富含谷氨酸（18.71%）、天冬氨酸（12.19%）、亮氨酸（7.87%）和赖氨酸（7.61%）。冷冻后，1.0 mg/mL AKAP 处理组的鼠李糖乳杆菌相对存活率（96.83%）明显高于生理盐水组（24.12%）（p<0.05）。AKAPs 还能延缓冷冻后鼠李糖乳杆菌酸化活性的丧失。AKAPs 的冷冻保护活性甚至优于三种商业冷冻保护剂（蔗糖、脱脂乳和甘油）。此外，AKAPs 还能显著减轻冷冻对鼠李糖乳杆菌β-半乳糖苷酶和乳酸脱氢酶活性的降低（p<0.05）。此外，AKAPs 能有效保护鼠李糖乳杆菌细胞膜的完整性，减轻细胞内物质的泄漏。这些发现表明，AKAPs 可以作为一种潜在的冷冻保护剂来保护鼠李糖乳杆菌，为利用脱脂南极磷虾提供了一种新的途径。
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