Comparison of concentration dependence of mechanical modulus in two biopolymer gel systems using scaling analysis

Concentration dependence of mechanical modulus of two biopolymer systems, i.e., xanthan-locust bean (X/L) mixture and fish muscle protein (surimi) was evaluated and compared at a wide range of polymer concentrations. A small amplitude oscillatory shear test was performed to measure changes in storage (G′) modulus during gelation and after gelation. Critical concentration (Cc) of the X/L mixture and surimi gel was determined to be 0.15 g/100 mL of solvent and 2.04 g/100 g of solvent, respectively. Reduced concentration (C_R=C_L/Cc) was used to compare the power-law dependence of modulus of the two systems. The elasticity exponent of the X/L mixture and surimi gel was determined to be 2.4 and 1.97, respectively. The concentration dependence of two biopolymer gel systems such as physical gels (X/L) and chemicals gels (fish muscle protein) theoretically demonstrated that the difference of flexibility of junctions in the networks might distinguish the elasticity of each gel.