地衣芽孢杆菌对草鱼肌原纤维蛋白凝胶特性的影响

Effect of Bacillus licheniformis on Gel Properties of Grass Carp Myofibrillar Protein

将地衣芽孢杆菌接种到草鱼肌原纤维蛋白中,研究不同贮藏温度条件下地衣芽孢杆菌对草鱼肌原纤维蛋白凝胶特性的影响。结果表明:地衣芽孢杆菌对草鱼肌原纤维蛋白凝胶特性和结构有较大影响。4℃和25℃贮藏条件下,随着贮藏时间的延长,凝胶强度、硬度、弹性和白度均呈下降趋势,且对照组下降幅度大于空白组;空白组和对照组凝胶的菌落总数均显著增加,自由水含量随着贮藏时间延长逐渐增加,对照组上升更明显,其保水性逐渐变差;场发射扫描电镜观察到凝胶微观结构被破坏,由紧密的网状结构逐渐变得疏松多孔;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gelelectrophoresis,SDS-PAGE)结果表明肌球蛋白重链和肌动蛋白逐渐被降解,且对照组凝胶的结构和蛋白降解程度均大于空白组。25℃条件下更适宜地衣芽孢杆菌的生长,样品凝胶破坏程度大于4℃条件下贮藏的样品。

The effect of inoculation with Bacillus licheniformis on gel properties of grass carp myofibrillar protein duringsubsequent storage at different temperatures was investigated. The results showed that gel properties were greatly affectedby Bacillus licheniformis, resulting in severely damaged gel structure. At 4 and 25 ℃,with the extension of storage time,gel strength, hardness, elasticity and whiteness showed a falling trend, and the control group presented a more significantdecrease than the blank group. The total number of colonies in the two groups increased significantly, and the free watercontent of myofibrillar protein gels increased gradually with storage period, especially significantly in the control group,which in turn showed poorer water retention capacities. Moreover, the microstructure of gels was damaged and became moreloose and porous, which was initially dense, as observed by FE-SEM. In addition, sodium dodecyl sulfate-polyacrylamidegel electrophoresis （SDS-PAGE） results showed that myosin heavy chain （MHC） and actin were gradually degraded. Thecontrol group displayed a higher degree of structure and protein degradation than the blank group. Bacillus licheniformisgrew better at 25 ℃, leading to more serious damage to the gel than at 4 ℃.