Studies on the mechanism of texture improvement by polysaccharide additions to Surimi gels using particle tracking and NMR

通过宏观、微观和分子观察，采用流变学、颗粒跟踪和光钳等手段，对添加多糖作为增强剂改善鱼糜凝胶品质的机理进行了研究。对不同多糖含量的鱼糜凝胶的宏观性质进行了评价。对照凝胶的模数较低，但随多糖的加入而增大。对于淀粉增强的鱼糜凝胶，低淀粉浓度的添加表现出与对照凝胶相似的模数。然而，在较高的浓度下观察到模数的增加，这表明淀粉从蛋白质凝胶网络中吸收水分，增加了蛋白质凝胶相中的蛋白质浓度。另一方面，即使在较低的多糖浓度下，添加和不添加KCl的KC增强的鱼糜凝胶的模数也有明显的增加。更有可能的是，KC作为一种功能性填充物，通过水胶体的阴离子基团和带正电的蛋白质与鱼糜蛋白相互作用。通过粒子跟踪和光学镊子的微观测量来研究凝胶的局部物理性质。测量了卡拉胶凝胶的随时间变化的松弛，方法是以大应变置换粒子，直到粒子从陷阱中释放出来，并跟踪释放粒子的反冲。不同卡拉胶凝胶颗粒反冲的应力松弛反映了凝胶微观流变性质的非线性特征。

The mechanism of polysaccharide addition as a reinforcer to improve Surimi gels' quality was investigated by macroscopic, microscopic, and molecular observation using rheological measurements, particle tracking, and optical tweezers. The macroscopic property of Surimi gels with different polysaccharides was evaluated. The control gel showed a low modulus but increased with the addition of polysaccharides. For starch reinforced Surimi gels, the addition of low starch concentration showed similar moduli with the control gel. However, an increase in the moduli was observed at higher concentrations, suggesting that starch absorbed water from the protein gel network, increasing the protein concentration in the protein gel phase. On the other hand, an apparent increase in the moduli was observed for KC reinforced Surimi gels with and without the addition of KCl even at low polysaccharide concentration. It is more likely that KC acted as a functional filler that interacts with the Surimi proteins via the anionic groups of the hydrocolloid and the positively charged proteins.Microscopic measurement using particle tracking and optical tweezer was performed to investigate the gels' local physical property. The time-dependent relaxation of carrageenan gels was measured by displacing the particle at a large strain until the particle was released from the trapped and tracking the recoil of the released particle. The stress relaxation of the particles' recoil for the different carrageenan gels suggests nonlinear features of the gels' microrheological properties.