Influence of dehydration-rehydration process on rheological properties of liquid fruit foods

The effects of the dehydration-rehydration process on the recovering of the original rheological characteristics of the re-hydrating solution were studied. Four different fruit fluid products were investigated: apricot, banana purees, non-pureed citrus fruits, i.e mandarin juice and lemon treacle, respectively. The static rheological behavior of both pureed and non-pureed products was measured for the raw material, i.e. before the drying process, and after the rehydration procedure. First of all, the results show that rehydrated materials have different rheological behaviors from fresh ones, especially in the case of starch added non-pureed products. Such differences can be due to both the stress conditions induced by mechanical drying and successive rehydration or to other factors such as, for example, the starch addition. These results were relevant to quantify the rehydration efficacy of pureed and non-pureed foods, suggesting than more than just one parameter should be controlled for liquid foods when the rehydration procedure is carried out