Stress-strain evaluation for characterization of polysaccharide gels behavior

MAMMARELLA, ENRIQUE J; DE PIANTE VICÍN, DANIEL A; RUBIOLO, AMELIA C

Santa Fe, Argentina

Congreso; 3rd Mercosur Congress on Process Systems Engineering and 1st Mercosur Congress on Chemical Engineering; 2001

Universidad Nacional del Litoral

The stress-strain of samples deformed until failure and the relaxation response after 50% deformation of the initial height under constant stress were obtained. Uniaxial compression and stress-relaxation tests allowed detecting satisfactorily changes in the mechanical resistance of gels with different alginate and carrageenan concentrations. Higher values of the initial force at the beginning of the relaxation test were associated with higher calcium uptake into gels. An increment of failure stress during uniaxial compression test for higher calcium concentration in the gel structure was also observed. The maximum cation amount uptake was higher than the theoretical value to saturate all the carboxylic groups available in alginate molecules due to structural rearrangements. Stress-relaxation tests indicated that the gel residual stress increased with higher k-carrageenan concentration.