Combined Use of Rheology, LF-NMR, and MRI for Characterizing the Gel Properties of Hairtail Surimi with Potato Starch

The effects of potato starch (4%, 8%, 12%, 16%, and 20%) on the gel properties of hairtail surimi were investigated by rheology, low-field nuclear magnetic resonance (LF-NMR), and magnetic resonance imaging (MRI). The results indicated that the addition of potato starch markedly improved the gel properties, including the maximum texture profiles, gel strength, and water holding capacity. The addition of potato starch significantly increased both the storage modulus and loss modulus after the formation of gel rather than changed the type of two curves. Furthermore, there was a positive correlation between heat-induced gel properties and rheological properties in the surimi-starch system. The LF-NMR results indicated that the addition of potato starch had a positive effect toward the shortening of T2 spin-spin relaxation time of gel and water exchange from free water to bound water. Additionally, more uniform water distribution in surimi gel contained potato starch was observed from the result of MRI. The overall results suggested that interactions of starch-protein promoted the most favorable properties of hairtail surimi at the addition of 16% potato starch.