纳米鱼骨钙在鱼肌球蛋白胶凝过程中的赋存形态及小尺寸效应

Fish bone is a natural and cheap source of calcium which possesses high bioavailability. However, huge amounts of fish bone were discarded as processing waste or used as animal feed. They may cause environmental pollution, apart from that it is waste of resource. Gel properties could significantly be promoted by nano-scaled fish bone. It might be related with the small size effect and occurrence mode of fish bone calcium. In this project, fish bone of different sizes (micronscale to nanoscale) will be produced from silver carp. Its critical size will be investigated by analyzing its dissociation constant, occurrence mode, effect of activating transglutaminase, and so on. The small size effect of nano-scaled fish bone will explored during gelling of fish myosin. The effect of nano-scaled fish bone calcium on myosin gelation property will be compared with several synthetic calcium with various typical occurrence modes. Dynamic equilibrium between occurrence modes of calcium will be investigated during gelling of fish myosin. The intrinsic relationship will be explored between calcium occurrence mode and myosin gelation property. Subsequently, the relative contribution to myosin gelation property will be compared between small size effect and occurrence mode of nano-scaled fish calcium. The regulating mechanism of nano-scaled fish bone calcium on gelation property will be elaborated on the basis of the small size effect and occurrence mode. The aim is to provide the theoretical basis for promoting gel properties of surimi and additional value for fish bone.

鱼骨是一种天然低价钙源，具有较高的生物利用率，然而目前大量鱼骨被丢弃或仅用作饲料原料，造成资源巨大浪费和环境污染。将鱼骨纳米化后可显著改善鱼糜的凝胶性能，推测这与纳米鱼骨的小尺寸效应及鱼骨钙的赋存形态有关。本项目拟以鲢鱼脊骨为原料制备不同尺度的鱼骨钙（微米级到纳米级），分析鱼骨钙的解离常数、赋存形态、TGase激活效应等跃变的临界尺寸；研究纳米鱼骨钙对鱼肌球蛋白组装行为及凝胶性能的影响，结合其理化特性参数，探讨纳米鱼骨钙在肌球蛋白胶凝中的小尺寸效应；研究几种典型赋存形态的合成钙及纳米鱼骨钙对肌球蛋白热胶凝特性的影响，同时分析钙在肌球蛋白胶凝过程中赋存形态间的动态平衡模式，剖析钙赋存形态与肌球蛋白胶凝特性的内在联系；比较分析纳米鱼骨钙在肌球蛋白胶凝过程中小尺寸效应与赋存形态作用的贡献率，进而揭示纳米鱼骨钙对肌球蛋白胶凝特性的调控机制，以期为鱼骨的高值化利用及改善鱼糜凝胶性能奠定理论基础。

鱼骨是一种天然低价钙源，具有较高的生物利用率，然而目前大量鱼骨被丢弃或仅用作饲料原料，造成资源巨大浪费和环境污染。将鱼骨纳米化后可显著改善鱼糜的凝胶性能，为探究纳米鱼骨对鱼糜胶凝特性的调控机制，项目在优化鱼骨微粒化（微米级到纳米级）工艺条件的基础上，分析了微粒化鱼骨理化特性，从纳米鱼骨的尺寸及钙的赋存形态角度分析了其对肌球蛋白胶凝特性的影响。结果表明，鱼骨经骨泥机处理可获得微米级鱼骨（MFB），进一步球磨处理可得纳米级鱼骨（NFB），与干法球磨相比，湿法球磨所得NFB的粒径更小更均匀，纳米鱼骨颗粒外形主要呈规则的多面体，颗粒带负电荷，其ZETA电位的绝对值随着纳米鱼骨颗粒粒径的降低而增加（p<0.05）。随着鱼骨粒度从微米级下降至纳米级，其溶解度及Ca2+的释放率显著提高，对内源性转谷氨酰胺酶（TGase）的激活作用也显著增大，NFB可促进鱼糜蛋白质在热胶凝过程中形成更多的非二硫共价键，进而形成连续致密的凝胶网络结构，提高其质构性能和持水性，NFB的适宜添加量为1%。此外，加热会进一步使部分化合态钙转化为离子态钙（Ca2+），Ca2+浓度进一步提高，在肌球蛋白之间形成钙桥，加热过程中钙赋存形态不断变化的缓释模式有利于肌球蛋白的胶凝，从而形成良好的凝胶质地。而MFB却会使鱼糜凝胶的网络结构发生断裂，降低其凝胶性能，纳米羟基磷灰石对照组也会破坏肌球蛋白凝胶网络的形成，降低其热胶凝特性。综上分析认为，纳米鱼骨对鱼糜凝胶的增强作用主要与纳米化后其理化特性的变化（尤其是离子态钙的增多）有关。本项目结果为水产加工副产物鱼骨的高值化利用提供了理论参考，同时对改善鱼糜凝胶的品质提供了一种新方法，具有较好的应用前景。