Estudo da secagem da polpa de açaí pelo método de camada de espuma

Abstract

The foam-mat drying was used as a dehydration method for açaí (Euterpe oleracea) pulp. Initially, the types of foaming agents were evaluated, also the influence of concentration’s and whipping times’ variation were evaluated for foam formation. By the choice of the best whipping time, the same diferente concentrations were used for the study of drying at different temperatures. For this, a prior study using a Central Composite Rotational Design were realized, which results have leading to a new experimental design to determine the best conditions of additive concentration and drying temperature, this time a 2² Factorial Design, with three central points were realized. The influence of the drying process conditions on the total anthocyanins, moisture, water activity and lightness (L*) was evaluated. Furthermore, an energy consumption study was performed based on the estimation of the equipment needed in the processes of obtaining dehydrated acai. This study allowed identify Emustab® as a good foaming agent for açaí foam, because it was produced foams with adequate density, expansion and stability for foam-mat drying. The drying temperature showed significative effects (p≤0,05) on total anthocyanins and moisture responses, whereas the effects statiscally significants (p≤0,05) for L* were concentration of additive and the interaction between concentration and temperature. The optimized condition was found by the desirability function. Still, estimation of energy consumption demonstrated the process of drying açai in foam layer as less energy intensive. Therefore, this study showed the feasibility of the technical and financial foam drying method for obtaining powdered açai pulp.