研究開始時の研究の概要 |
The mechanism of texture improvement of Surimi gels is scarcely studied especially from the microscopic and molecular viewpoint. In this fiscal year, rheology, particle tracking and NMR measurements will be performed to clarify the mechanism of improvement of Surimi gels from different perspectives.
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研究実績の概要 |
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.
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