Modeling creep/recovery behavior of cold-set gels using different approaches

This study aimed to characterize cold-set unfilled and emulsion-filled gels (EFG) of commercial soy protein isolate (SPI), with and without xanthan gum (XG) and locust bean gum (LBG), using creep/recovery tests. For this purpose, a comparative study of the data was developed using two different approaches:(1) the classical Burger's model and (2) a fractional derivative approach. The polysaccharides incorporation decreased the gels' creep compliance and increased the recovery rates. Systems with XG presented lower creep compliance and higher recovery capacity. EFG were stronger and exhibited higher elasticity than unfilled gels. Burger's model parameters allowed some comparisons among the systems, however, due to their lack of clear physical meanings they did not allow an in-depth discussion on the gels' properties. Besides, this model did not describe well recovery data as the fractional derivative approach, whose parameters with clearer physical meanings, allowed a more intuitive discussion about the characteristics of the gels.