Effects of crude fucoidan on physicochemical properties, antioxidation and bacteriostasis of surimi products

In this study, we evaluated the effects of crude fucoidan on the physicochemical properties and biological activities of surimi gels. The gel strength and water holding capacity of surimi products significantly increased by adding 0.125% of fucoidan, and reduced with the further addition of fucoidan. Crude fucoidan exhibited little effect on the textural properties and protein content of surimi products. Moreover, the whiteness of surimi gels was inversely proportional to fucoidan concentrations. The scanning electron microscopy analysis suggested fucoidan at low concentration promoted the cross-linking of protein and the densification of gel network structure to improve the gel properties of surimi products, while excessive fucoidan hindered the cross-linking of proteins resulting in the formation of loose and inhomogeneous microstructure. Interestingly, the biological activities analysis revealed the homogenates from surimi gels containing fucoidan exhibited potent DPPH, ABTS, hydroxyl radical scavenging capacity, and reducing capacity, also displaying significant bacteriostatic effects on both Escherichia coli and Staphylococcus aureus in concentration-dependent manners.