School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, Hunan Province, China; Hunan Provincial Engineering Technology Research Center of Aquatic Food Resources Processing, Changsha 410114, Hunan Province, China.
School of Food Science and Bioengineering, Changsha University of Science & Technology, Changsha 410114, Hunan Province, China.
Food Chem. 2024 Jan 15;431:137114. doi: 10.1016/j.foodchem.2023.137114. Epub 2023 Aug 9.
This study investigated the cryoprotective mechanism of ultrafiltration membrane-separated fractions (>10 kDa, UF-1; 3-10 kDa, UF-2; and <3 kDa, UF-3) derived from silver carp hydrolysates on frozen surimi. The surimi gel incorporating UF-3 exhibited a compact, continuous structure with uniform pores, even after undergoing six freeze-thaw (F-T) cycle, with the minimal reduction in entrapped water (from 95.1 % to 91.1 %) and least increase in free water (from 4.5 % to 6.6 %) as revealed by SEM and LF-NMR analysis. Through molecular docking analysis, three major peptides in UF-3 were identified to form robust interactions with the myosin head pocket, facilitated by hydrogen bonds, electrostatic forces, and hydrophobic interactions. Furthermore, molecular dynamics simulations demonstrated that the three peptides effectively prevented myosin from unfolding and aggregating by tightly binding to basic amino acids (Arg, Lys) and hydrophobic amino acids (Phe, Leu, Ile, Met, and Val) residues in the myosin head pocket, primarily governed by electrostatic energies (-156.95, -321.38, and -267.53 kcal/mol, respectively) and van der Waals energies (-395.05, -347.46, and -319.16 kcal/mol, respectively). Notably, the key action site was identified as Lys599 on myosin. The hydrophilic and hydrophobic hotspot residues of the peptides worked synergistically to stabilize the myosin structure in frozen surimi.
本研究考察了源自银鱼水解产物的超滤膜分离级分（>10 kDa、UF-1；3-10 kDa、UF-2；和<3 kDa、UF-3）对冷冻鱼糜的抗冻保护机制。在经过六次冻融（F-T）循环后，结合 UF-3 的鱼糜凝胶仍呈现出紧密、连续的结构，具有均匀的孔，甚至在最小程度上减少了包埋水（从 95.1%减少到 91.1%）和自由水的增加（从 4.5%增加到 6.6%），这一点通过 SEM 和 LF-NMR 分析得到了证实。通过分子对接分析，确定了 UF-3 中的三种主要肽与肌球蛋白头部口袋形成了强大的相互作用，这是通过氢键、静电力和疏水力来促进的。此外，分子动力学模拟表明，这三种肽通过与肌球蛋白头部口袋中的碱性氨基酸（Arg、Lys）和疏水性氨基酸（Phe、Leu、Ile、Met 和 Val）残基紧密结合，有效地防止了肌球蛋白的展开和聚集，主要由静电能（分别为-156.95、-321.38 和-267.53 kcal/mol）和范德华能（分别为-395.05、-347.46 和-319.16 kcal/mol）控制。值得注意的是，关键作用位点被确定为肌球蛋白上的 Lys599。肽的亲水和疏水热点残基协同作用，稳定了冷冻鱼糜中的肌球蛋白结构。
