冻藏对斑点叉尾鮰鱼片蛋白质冷冻变性和肌原纤维超微结构的影响

Effects of Frozen-storage on Protein Denaturation and Ultrastructure of Channel Catfish (Ictalurus Punctatus) Fillet

目的:研究不同冻藏温度及抗冻剂对鮰鱼片蛋白质冷冻变性和肌原纤维超微结构的影响。方法:鮰鱼剖片后一部分置于-18、-30和-50℃3种温度下冻存15个月,另一部分先用三聚磷酸钠混合液浸渍2min,取出沥干,10min后置于上述温度下,测定冻藏前、后各品质指标的变化情况。结果:鮰鱼片3种不同温度冻藏15个月后,粗脂肪和粗蛋白含量下降,pH值下降,TVB-N值和K值上升,盐溶蛋白的含量下降,Ca2+-ATPase活性降低,鱼肉营养品质下降,蛋白质发生冷冻变性。冻藏温度越低,蛋白质的冷冻变性程度越轻,纵肌切片基本结构特征保持较好。添加多聚磷酸盐抗冻剂有助于保持鱼片的营养品质,降低蛋白质冷冻变性。结论:冻藏温度对鮰鱼片蛋白质冷冻变性和超微结构有显著影响,抗冻剂可有效防止蛋白质的冷冻变性。

Objective： To investigate effects of different frozen storage temperatures and salt solutions on protein denaturation and uhrastructure of channel catfish fillet. Methods： channel catfish fillet were treated for 2 rain with or without salt solutions, and then frozen into -18, -30 and -50℃ for 15 months. Results： channel catfish fillet exhibited lower contents of fat and protein, pH, extractable protein nitrogen value, and Ca2＋-ATPase activity, and higher TVB-N value and K value after storages at -18, -30 and -50℃ for 15 months than those were before frozen storage, which indicated that channel catfish fillet had a decrease in nutritive quality and the protein denaturated. Frozen storage temperature was lower, the degree of protein denaturation lighter and cell ultrastructure of tissues better. In addition, soaking cryoprotectants in fillet maintained nutritive quality and reduced the protein denaturation. Conclusion： frozen storage temperatures markedly affect the protein denaturation and ultrastructure, and cryoprotectants effectively eased the protein denaturation of channel catfish fillet when stored at frozen temperatures.