Effect of Tapioca Starch on Gel Characteristics of Threadfin Bream Surimi

Abstract

This study investigated the effect of adding tapioca starch (2.5, 5, 7.5, and 10% by weight of surimi) on gel characteristics of threadfin bream surimi (Nemipterus hexodon). Surimi gels were analyzed whiteness, gel strength, expressible water, and microstructure by scanning electron microscopy (SEM). Whiteness of samples with tapioca starch was significantly lower, but gel strength was significantly higher than for the control sample (p < 0.05). Samples with 10% tapioca starch had the highest gel strength value (951 ± 61.86 g.cm). However, sample gel strength with tapioca starch did not significantly differ (p > 0.05). Adding tapioca starch lowered expressible water, accompanied by increased gel strength. Expressible water decreased when tapioca starch concentration increased (p < 0.05). Sample expressible water with 10% tapioca starch was lower by 50% than for the control sample. Surimi gels with tapioca starch has denser and more uniform microstructure than the control sample. As starch concentration increased, gel network microstructure became more compact, and voids within the fiber network reduced in size. These results were concomitant with gel strength and expressible water. Therefore, adding tapioca starch functioned as a filler in the gel matrix. The optimum concentration of tapioca starch to improve the gel characteristics was 7.5% by weight of surimi.