Secagem em camada de espuma do suco da romã, composto por sua polpa e casca

Abstract

Pomegranate (Punica granatum L.) has been widely studied because of its high antioxidant power. There are several studies that prove the effectiveness of various parts of this fruit in the treatment of various diseases. It is a seasonal fruit, which makes it impossible to be available at all seasons and, because it has a high water content, its storage for long periods of time is not feasible, since this humidity facilitates the proliferation of microorganisms and reactions that their degradation. The foam-mat drying may be an option for the preservation of the active principles of this fruit, since the removal of the water hinders the proliferation of the microorganisms and the deterioration reactions. Aiming at this, the main objective of this work was to obtain pomegranate juice powder, composed of its pulp and bark, using a foam-mat drying. The characteristics of the foam interfere significantly in the drying success, therefore, the physical characterization of the foam produced was analyzed, analyzing its stability, density, air incorporation capacity, expansion and humidity. The drying process followed a complete factorial experimental planning 24 + 4 central points, totaling 20 experiments, where the independent variables were: drying temperature (50, 60 and 70oC); concentration of bark in the juice (20, 25 and 30%); concentration of the blowing agent (3, 4 and 5%); and agitation time (2, 3 and 4 minutes) and the influence of these variables on the process dependent variables (drying time and equilibrium moisture) and the powder characteristics were evaluated through statistical analysis. The drying kinetics curves and the adjustment to the mathematical models most used in the literature were produced with the drying data. With the results it was observed that the agitation time was the variable that most affected the physical characteristics of the foam and that temperature was the variable that most influenced the drying time. The mathematical models that best fit the data were Page and Page Modified. The active principles of pomegranate, such as phenolic compounds and antioxidant activity, were concentrated and preserved by foam-mat drying, indicating that this technique is feasible to obtain the powder of this fruit.