The conventional three-component and the elastic thermalization lifetime analyses (ETLA) are used for the characterization of collagen biopolymer. The samples were prepared by mixing collagen with plasma water. The solution concentrations 0, 20, 50, 100, 200 and 400 g/l were chosen in order to cover the possible range of biological compositions. The evaluation of cavity radii is deduced from the infinite potential model, for the conventional analysis, and from a finite potential formulation, in the case of ETLA. The ETLA results are much more sensitive to changes in composition of the samples than the conventional analysis. In addition, the correlation between the Ps contribution and its pickoff lifetime in bulk implies that Ps production is enhanced by higher electron density. Therefore, microscopic parameters related to the material composition and structure can be reached.