Abstract：
Protein oxidation during chilling and frozen storage has recently attracted great attention due to its consequences on protein solubility and functionality. In this study, the effects of kappa-carrageenan oligosaccharides on myofibrillar protein oxidation in peeled shrimp (Litopenaeus vannamei) during frozen storage were investigated by assessing the content of the carbonyls, total sulfhydryl, dityrosine, and surface hydrophobicity. We also examined the means of antioxidant activity in vitro, degradation of muscle proteins, and integrity of tissue structure. Our data revealed that in vitro carrageenan oligosaccharides exhibited good capacities of OH, O2-, and DPPH· scavenging and Fe2+-chelating activity. Chemical analyses showed that frozen storage increased susceptibility of myofibrillar proteins to frozen oxidation. We found that the incorporation of carrageenan oligosaccharides during the treatment of the shrimp prior to frozen storage significantly decreased the formation of protein carbonyl and dityrosine, lowered the changes in myofibrillar surface hydrophobicity, and maintained a higher total sulfhydryl content when compared with the water-treated samples (control). Additionally, the results of protein degradation and tissue structure confirmed that these antioxidant oligosaccharides exhibited marked effects on stability of muscle proteins and effectively inhibited the degradation/oxidation of muscle proteins during frozen storage. Overall, the contribution of the antioxidant activities played an important role in cryoprotective effects of carrageenan oligosaccharides on frozen shrimp. Further application of these findings might maintain better quality and extend the commercialization of refrigerated products.
摘要：
由于其对蛋白质溶解度和功能的影响，冷冻和冷冻储存过程中的蛋白质氧化最近引起了极大的关注。在这项研究中,通过评估羰基化合物的含量，研究了κ-角叉菜胶寡糖对去皮虾（凡纳滨对虾）冷冻储存过程中肌原纤维蛋白氧化的影响，总巯基，二酪氨酸,和表面疏水性。我们还检查了体外抗氧化活性的方法，肌肉蛋白质的降解，和组织结构的完整性。我们的数据显示，体外卡拉胶寡糖表现出良好的OH容量，O2-,以及DPPH·清除和Fe2+螯合活性。化学分析表明，冷冻储存会增加肌原纤维蛋白对冷冻氧化的敏感性。我们发现，在冷冻储存前处理虾的过程中，卡拉胶寡糖的掺入显着降低了蛋白质羰基和二酪氨酸的形成，降低了肌原纤维表面疏水性的变化，与水处理样品（对照）相比，保持了较高的总巯基含量。此外,蛋白质降解和组织结构的结果证实,这些抗氧化寡糖对肌肉蛋白质的稳定性具有显著影响,并能有效抑制冷冻保存过程中肌肉蛋白质的降解/氧化。总的来说,抗氧化活性的贡献在卡拉胶寡糖对冷冻虾的冷冻保护作用中起重要作用。这些发现的进一步应用可能会保持更好的质量并延长冷藏产品的商业化。
