淡水鱼肉蛋白质组成及其在鱼糜制品加工中的变化

Protein Components of Freshwater Fish Flesh and Their Changes during Surimi-based Processing

本文通过鱼肉蛋白质组成、鱼糜凝胶特性的测定及SDS-PAGE凝胶电泳,研究了鲢、鳙、草、鲫四种淡水鱼鱼糜凝胶特性及其凝胶形成过程中蛋白质组成的变化。四种淡水鱼肉粗蛋白质含量基本相同,但凝胶特性存在明显差异,其原因是四种淡水鱼肉的盐溶性蛋白含量不同。在鱼糜制品加工过程中,盐溶性蛋白质、水溶性蛋白的比例逐渐下降,而不溶性蛋白比例逐渐上升。弹性凝胶体的形成始于盐擂阶段,主要形成于低温凝胶化阶段。SDS-PAGE凝胶电泳图谱显示,肌球蛋白重链的量在鱼糜凝胶形成过程中明显减少,而肌球蛋白轻链和肌动蛋白的量几乎未发生变化。肌球蛋白重链在内源转谷氨酰胺酶作用下,发生分子间或分子内的ε-(γ-Glu)-Lys共价交联,形成了网络状的不溶性蛋白。

The gel properties and the protein component changes during surimi gel forming of freshwater fishes, Sliver Carp, Bighead, Grass Carp and Crucian Carp, were investigated by assaying the protein components and gel properties and SDS-PAGE electrophoresis. The contents of crude protein in these fish species were not much different. However, the gel strength in surimi gel was obviously different because of the difference in the content of salt-soluble protein. The percentage of salt-soluble protein and water-soluble protein decreased gradually during surimi-based products manufacturing, while that of the insoluble protein increased. Elastic gel formed from meat smashing with salt and formed mainly during low temperature setting. SDS-PAGE pattern showed that the content of myosin heavy chain （MHC） decreased obviously during sudmi gel forming, while that of the myosin light chain （MLC） and actin had no change. Trausglutaminase （TGase） catalysed the formation of gamma-Glu-epsilonLys isopeptide bonds among myosin heavy chain and created the insoluble protein with network structure.