Effect of Kappaphycopsis cottonii powder/konjac composite on the characteristics of tuna (Thunnus sp.) fish balls

The effect of Kappaphycopsis cottonii powder/konjac composite as a natural thickener in fish balls formulation was investigated. A series of combinations of K. cottonii powder/konjac with the ratio of 5:0, 4:1, 3:2, 2:3, and 1:4 (w/w) was used. The K. cottonii powder/konjac combinations were analysed for their gel strength, elasticity, whiteness, and gelatinisation profile using a Rapid Visco Analyzer. The best combination of the composite powder was further used in the formulations of tuna fish balls at levels of 0, 0.5, 1, 1.5, 2, and 2.5% (w/w). The fish balls were characterized for their chemical properties (moisture, ash, protein, fat content), texture profile (hardness, adhesiveness, springiness, gumminess, chewiness), colour, and sensory attributes. The results showed that the K. cottonii powder/konjac (4:1 w/w) produced the gel with the highest elasticity and whiteness, thus it is preferred to use in the fish balls formulation. The incorporation of composite powder into tuna fish balls formulation produced a significant effect on the color of the fish balls. The addition of 1% of the composite powder produced fish balls with high springiness and chewiness.