The effect of concentration on viscoelastic properties of chestnut and acorn starch is discussed in the paper. The starch structure was assessed using a rheological fractional standard linear solid model FSLSM in contrary to very simple power-law model usually used in many published papers concerning determination of rheological properties of starch. Rheological parameters of this model were determined and their changes for different concentrations of the two tested types of starch were discussed. The values of the rheological parameter of FSLSM model give a useful of information concerning the elastic properties of materials such as total elasticity of networks, network oscillations, gel stiffness, structure of cross-linking and relaxation time of the materials. The proposed method for the interpretation of rheological measurements of the two types of starch allows for a comprehensive estimation of the analyzed biomaterial structure. The fractional rheological models can be very useful to control the biomaterial structure the needs of the final to meet envisaged product which is particularly significant from the point of view of materials engineering.