Secagem de extrato aquoso de folhas de veludo branco (Guettarda viburnoides) por spray drying e liofilização

Abstract

Guettarda viburnoides, popularly known as "white velvet", has been used in the form of infusion of the leaves for the treatment of inflammations. Due to the fact that the plant in natura presents a high water content, its long-term preservation becomes unfeasible, because the high water content facilitates the proliferation of microorganisms and enzymatic reactions, causing its deterioration or degrading the active principle. The present work aims to study the spray drying and freeze-drying techniques of Guettarda viburnoides leaves, evaluating the bioactive compounds and analyzing the technological properties of the powdered extract. The extract was obtained by aqueous infusion of G. viburnoides leaves, and dehydrated by atomization (A) and lyophilization (L1 and L2) methods, being A and L1 using mixture of G. viburnoides extract (60%), distilled water (16%) and encapsulating agents consisting of maltodextrin solutions (8%), gum Arabic (8%) and chitosan (8%), and L2 using extract (100%). The powdered extract (A) presented low yield (3.40%) if compared to L1 (11.54%) and L2 (4.198%), however, it presented the best physical characteristics, obtaining spherical capsules with low humidity (3.61%) and water activity (0.41 Aw), with density (0.334 g/cm3) and solubility (84.47%) similar to the freeze-dried product and with less hygroscopicity (13.49%), providing adequate conditions for prolonged conservation. The spray drying (A), despite the high temperature of the process, was efficient in retaining phenolic compounds and flavonoids and showed antioxidant activity similar to L1. It is concluded that the powdered extracts obtained by spray drying and lyophilization present potential to be used in the formulation of supplements, pharmaceuticals and cosmetics.