Preparation of multipolymer hydrogel system-based boiled fish analog for mimicking fish muscle fiber: Combination of heat and non-heat matrixes

The aims of this study were 1) to prepare boiled fish analog (BFA) by mixing soy protein isolate (SPI) and fish gelatin (FG) cross-linked by transglutaminase (TGase) in a non-heat matrix with κ-carrageenan (Car) and locust bean gum (LBG) in a heat-matrix and 2) to analyze a change in chemical, textural, and morphological properties of BFA. The visual appearance, fish muscle fiber shape, and surface color of BFA samples were successfully similar to those of boiled Convict grouper. Furthermore, the results of FE-SEM exhibited increase the fish muscle fiber shape on the surface of BFA with an increase in the concentration of TGase. The chemical characterization of BFA samples using FT-IR and XRD exhibited considerable changes in characteristic peaks due to the interaction of fragment molecules to polysaccharides by heating and long-chain proteins by TGase. The increasing concentrations of TGase in the BFA enhanced the solvent holding capacity, hardness, springiness, and shear force properties of BFA. These phenomena could be explained by the morphological results of CLSM images of BFA samples, which displayed the smaller and denser droplets with increasing concentrations of TGase. Overall, the results of this study suggested that BFA samples can be applied to the first alternative fish meat products by mimicking fish muscle fiber in the food industry.