白鲢鱼鳞抗冻多肽的制备及对冻融鱼糜凝胶特性的改善作用

Preparation of Silver Carp Scale Antifreeze Peptides and Its Improvement Effect on Gel Properties of Frozen-thawed Surimi

本研究以白鲢鱼鳞为原料,通过生物酶解制备白鲢鱼鳞抗冻多肽(ScAFPs)。以嗜热链球菌冻融存活率为主要指标,以水解度为辅助指标,通过单因素实验及响应面试验优化,得到ScAFPs最佳酶解制备工艺;同时进行ScAFPs的基本性质及其对鱼糜凝胶稳定性影响的研究。结果表明,选用的酶制剂为胰蛋白酶、底物浓度5.0%、酶底比3.8%、酶解温度37℃、酶解时间3.5 h,此条件下制备的ScAFPs对嗜热链球菌冷冻存活率为82.19%±1.03%,水解度为7.54%±0.43%。ScAFPs相对分子量主要集中于180~3000 Da之间,等电点在4.2左右,且具有极强的亲水性和较好的热稳定性,能有效降低体系冰晶含量。ScAFPs对冻融鱼糜的凝胶特性的影响结果表明,经过5次冻融循环后,ScAFPs处理组鱼糜凝胶白度、硬度、咀嚼性、凝胶强度等指标下降幅度均显著(P<0.05)低于未添加低温保护剂的鱼糜组,且当ScAFPs添加量超过2%时,ScAFPs对鱼糜的冻融保护效果优于商业抗冻剂(4%蔗糖与4%山梨醇混合物)。本研究为利用白鲢鱼鳞加工副产物开发新型低温保护剂并探索在冷冻鱼糜及凝胶制品的应用奠定理论基础。

In this study, silver carp scale antifreeze peptides(ScAFPs) were prepared by enzymatic hydrolysis. Taking the freeze-thawing survival rate of Streptococcus thermophilus as the main index and the degree of hydrolysis as the auxiliary index, the optimal enzymolysis preparation process of ScAFPs was obtained through single factor and response surface optimization. At the same time, the basic properties of ScAFPs and their influence on the gel stability of surimi were studied. The results showed that the selected enzyme preparation was trypsin, substrate concentration of 5.0%, enzyme dosage of 3.8%, enzymolysis temperature of 37℃, enzymolysis time of 3.5 h. Under these conditions, the frozen survival rate of ScAFPs against Streptococcus thermophilus was 82.19%±1.03% and the degree of hydrolysis was 7.54%±0.43%.The relative molecular weight of ScAFPs was mainly in the range of 180~3000 Da, and its isoelectric point was around 4.2.Moreover, ScAFPs had strong hydrophilicity and good thermal stability, which could effectively reduce the ice crystal content in the system. The effect of ScAFPs on gel properties of freezing-thawing surimi showed that after five freezingthawing cycles, the decrease of gel whiteness, hardness, chewiness and gel strength of surimi treated by ScAFPs was significantly(P<0.05) lower than that of surimi without cryoprotecter. When the addition of ScAFPs exceeded 2%, the freeze-thaw protection effect of ScAFPs on surimi was better than that of commercial antifreeze agents(4% sucrose and 4%sorbitol mixture). This study lays a theoretical foundation for the high-value utilization of silver carp scales and the application of ScAFPs as a new type of cryoprotectant in frozen surimi and its gel products.