1980 Volume 27 Issue 5 Pages 227-233
A description of a new apparatus for the measurement of viscoelasticity of gel-like foods was given. Complex Young's modulus E*=E′+iE″ of gels can be obtained easily and rapidly by means of this apparatus. E′ and E″ of agar-agar and gelatin gels were determined for various concentrations. E' of these gels were proportional approximately to the square of the concentration. The values of the mechanical loss tangent of gelatin gels were larger than those of agar-agar gels. Temperature dependence of E′ and E″ of gelatin gels were also examined. Force-deformation curves were obtained for these gels in the case of uniaxial compression with a constant speed. The breaking strength of gelatin gels was much larger than that of agar-agar gels. It was very difficult to obtain force-deformation curves for gelatin gels with good reproducibility. The breaking process of gelatin gels was recorded photographically at regular time intervals. It was concluded that the dynamic measurement in the range of small deformation is an appropriate method for evaluating the quality of gel-like foods.
