Investigation of the Gel Properties and Gelation Mechanism of a Surimi Blend Composed of Skipjack Tuna (Katsuwonus pelamis) and Purpleback Flying Squid (Symplectoteuthis oualaniensis)

The objective of the present study was to investigate the gel properties and gelation mechanism of a surimi blend consisting of <i>Katsuwonus pelamis</i> and <i>Symplectoteuthis oualaniensis</i>. Superior gel properties, including gel strength, cooking loss and water holding capacity, were observed in mixed surimi. With increasing proportions of <i>K. pelamis</i> in the blend, an increase in hardness, gumminess and chewiness emerged, which compromised the resilience and whiteness of the gels. The detection of apparent viscosity revealed the shear-thinning properties of mixed surimi. The results of the molecular force measurements and differential scanning calorimetry demonstrated that heterogeneous myofibrillar proteins interacted into rigid protein aggregates with the help of enhanced hydrophobic interactions, subsequently increasing the values of G' and G". According to the FTIR spectrum, as the proportion of <i>K. pelamis</i> gradually increased, the protein secondary structure of surimi transitioned from a random coil to a <i>β</i>-sheet, facilitating the formation of a more ordered network structure. A marked improvement in the microstructure was observed via SEM. Therefore, the incorporation of surimi can be employed to optimize gel properties.