The effect of butter oil and whey proteins addition on viscoelastic properties of confectionary Dulce de Leche was evaluated. A two factors experimental design (0-8 % p/v of butter oil and 0-1 % p/v of whey proteins) was analysed. Frequency sweep tests were carried out and for all formulations studied a weak gel like behavior was observed. Therefore, results were interpreted using a weak gel model for foods. It was observed that the rheological behavior of the sample with addition of whey proteins and butter oil is significantly different than the others because rheological units interact with greater strength. Even more, the sample without butter oil and with whey proteins addition is composed by less rheological units than the others. It is concluded that the whole addition of butter oil and whey proteins generates a stronger gel matrix, more appropriate for use in confectionary

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 enabled satisfactory differentiation of the mechanical resistance of gels with different alginate and carrageenan concentrations. Higher values for initial force at the beginning of the relaxation test were associated with higher calcium uptake by the gels. An increment of failure stress during the uniaxial compression tests for higher concentration of calcium in the gel structure was also observed. The maximum amount of cation uptake was higher than the theoretical value for saturation of all the carboxylic groups available in alginate molecules due to structural rearrangements. Stress-relaxation tests indicated that the residual stress of the gel increased with kappa-carrageenan concentration.