【作者】 李艳青；

【导师】 孔??；

【作者基本信息】 东北农业大学 ， 食品科学， 2004， 硕士

【摘要】 我国淡水鱼养殖业发展很快，但加工业相对落后，目前淡水鱼一般都是就地鲜销，很少用于加工。我国产量较高的鲢鱼虽然具有很好的加工和凝胶特性，但由于其蛋白质容易发生凝胶劣化而影响了它的加工利用。本课题以低值淡水鱼－鲢鱼为研究对象，通过控制其内源组织蛋白酶、添加外源转谷胺酰氨酶以及在冷冻鱼糜中添加抗冻剂等措施来提高鱼糜的凝胶强度，抑制蛋白变性，改善鱼糜的品质。研究表明，鲢鱼肌肉中的内源组织蛋白酶在鱼糜凝胶劣化中起重要作用。 鲢鱼宰后随着时间的延长，组织蛋白酶L和组织蛋白酶B都呈下降趋势，而组织蛋白酶H鱼宰后在30min达到最高。组织蛋白酶L和组织蛋白酶H的最适作用温度为55℃，而组织蛋白酶B在45℃达到最高。组织蛋白酶对热的耐受性较强，温度超过65℃组织蛋白酶活性下降很快，到85℃基本全部失活。组织蛋白酶活性的最适pH值在5～7之间，说明组织蛋白酶是一种偏酸性蛋白酶。漂洗和加盐擂溃可以有效的降低三种组织蛋白酶的活性，试验证明NaHCO3溶液是较理想的漂洗溶液。添加非肌肉蛋白和E64 都可以显著的降低鱼肉中组织蛋白酶的活性。通过SDS-PAGE电泳试验得出, 在室温放置30min后，鱼肉中的肌球蛋白重链几乎完全消失。鱼肉中组织蛋白酶在55℃时有较高的活性，在此温度下，肌球蛋白重链降解最严重。通过电镜试验得出,鱼肉中的组织蛋白酶对鱼肉的微观结构影响较显著。鱼肉在55℃处理后，肌原纤维肌节完全被破坏，明暗线消失；鱼宰后在55℃下放置60min时，肌节断裂严重，肌节结构完全破坏。 添加外源的转谷氨酰胺酶可以有效的提高鱼糜的凝胶强度，试验得出转谷氨酰胺酶的最优作用条件是添加量为6％、作用温度为40℃、作用时间为1.5h，作用pH值为7。添加抗冻剂低聚糖、蔗糖、山梨醇都可以有效的防止鱼糜在冷冻过程中蛋白发生变性，并能提高冷冻鱼糜的凝胶强度，混合磷酸盐能有效的提高冷冻鱼糜的保水性。通过试验得出四种抗冻剂的最佳配比是：低聚糖的添加量为4％、山梨醇的添加量为2％、蔗糖的添加量为1％、混合磷酸盐的添加量为0.3％。更多还原

【Abstract】 Our country freshwater fish breeding developed very quickly, yet processing fall behind relatively. At present freshwater fish oridinarily saled in fresh , seldom was used to process. Although the silver carp had very good processing and gel property, yet it was limited to use because of its protein tendding to morori. This thesis took the freshwater fish silver carp as the research target, by means of dominating endogenous cathepsin and increasing outward transglutaminase and cryoprotection to improve the gel strength of surimi and restrain the denaturalization.Research made known, endogenous cathepsin in the silver carp muscle took the significant action in surimi morori. Cathepsin L and cathepsin B presented descent tendency after slaughter, cathepsin H attained highness in 30min after slaughter. The optimum temperature of cathepsin L and cathepsin H was 55 ℃，but cathepsin B was 45 ℃. Cathepsin had strong resistant to high temperature, when the temperature overtook 65 ℃, the activation of cathepsin dropped very quickly, up to 85 ℃，it essentially completely losing lives. The optimum pH of cathepsin was 5~7. Washing and chopping with salt could cut down the activation of all 3 kinds of cathepsin. The experiment demonstrated that NaHCO3 solution was more ideal. Increasing non-muscle protein and E64 could reduce the activation of cathepsin.By means of SDS-PAGE electrophoresis, it was known that cathepsin had high activation at 55℃, at this temperature myosin degradation severely.30min after slaughter, myosin nearlly disappeared. By electron microscope, it was known cathepsin had an significant effect on microstructure of fish muscle.Increasing outward transglutaminase had an important effect on improving gel strength of surimi. It was demonstrated that the optimum dosage, optimum reaction temperature, optimum reaction time and reaction pH of transglutaminase was 6%, 40℃, 1.5h, and pH7 differently.Increaseing cryoprotection as oligosaccharides, sorbitol, sucrose, could resist denaturalization of protein in surimi effectively. Mixed phosphate improved the water-holding capability of surimi. Obtained by means of the experiment :the optimum dosage of 4 kingds of cryoprotection was that oligosaccharides was 4%, sorbitol was 2％，sucrose was 1%，mixed phosphate was 0.3% respectively. Postgraduate:Li Yanqing Specialty:Food Sciene Supervisor: Prof.Kong Baohua更多还原