Secagem convectiva de polpas combinadas de noni e umbu.

Abstract

The present work was developed aiming to obtain a powder product from the combination and dehydration of noni pulp (Morinda citrifolia L.) and umbu (Spondias tuberosa Arruda Câmara), which were formulated in three different proportions, being the first formulation consisted of 75% noni pulp and 25% umbu pulp, the second formulation was 50% noni pulp and 50% umbu pulp and the third was 25% noni pulp and 75% umbu pulp. The formulations were dehydrated by the foam mat drying process in a fixed bed dryer, varying the air velocity (1.0, 1.5; and 2.0 m/s) and drying temperature (40, 50 , 60 and 70 °C). Initially the pulps were formulated and beaten in a domestic mixer, obtaining foam without the aid of foaming agents. The physical, chemical and physicochemical characterization of the foams was performed followed by the drying process, thus obtaining the drying kinetics and adjusting the Henderson and Pabis, Lewis and Page models to the experimental data. Subsequently, the physical, chemical and physicochemical characterization of the obtained powders was made. Noni pulp showed high foaming capacity, requiring no additives. Drying time was reduced with increasing air temperature. The Page model was the best fit to the experimental data. The powders presented high levels of vitamin C, especially for the formulation that contained higher proportion of noni pulp. For all formulations, as the drying temperature increased, an increase in pH values was noticeable, while total titratable acidity and luminosity decreased. The moisture contents and water activities of the powders presented low levels, indicating to be adequate when subjected to a safe storage.