Secagem por camada de espuma da polpa de açaí (Euterpe oleracea Mart)

Abstract

Açaí has a high content of anthocyanins and antioxidants in its composition. Usually its pulp is sold frozen, which has a high energy value. Drying would be an alternative to obtain products with low moisture content and stability to facilitate the transport and storage process. The present study aimed to prepare and produce açaí foam with emulsifier concentrations of 2% and 0%, proceeding with drying (60oC) in a forced air circulation oven. The diffusion coefficient was determined for the pulp with 2% Emustab® (5.35x10-4 cm2/s) and for the pure pulp (1.41x10-4 cm2/s). The formation of pores, resulting from aeration in the pulp with emulsifier, resulted in a higher diffusion coefficient, with less drying time. The sorption isotherms showed that the models presented excellent mathematical adjustments at temperatures of 25o C and 35oC for the two samples of açaí powder, with R2> 0.95 and R2> 0.91 respectively. The content of anthocyanins (4.28  0.08 mg/g powder 0% Emustab® and 2.69  0.20 mg/g powder 2% Emustab®), DPPH antioxidant activity (29.34  0.002 powder 0% Emustab® and 91.81  0.03 powder 2% Emustab®), solubility for powder with 2% Emustab® (47.93%  0.02) and for powder with 0% Emustab® (19.72%  0.028), microstructure and rehydration time (168 ± 0.05 s powder with 2% Emutab® and 324s ± 0.11 powder 0% Emustab®). In this condition of 2% Emustab®, a porous powder was obtained with good fluidity, solubility and antioxidant capacity.