Effect of operating conditions on the yield and quality of açai (Euterpe oleracea Mart.) powder produced in spouted bed

- Drying of açai in spouted bed was feasible from the processing perspective.
- The process yield was positively influenced by all the variables studied.
- Açai powder moisture was specially influenced by the drying air temperature.
- The increase of airflow rate decreased significantly the anthocyanin content.
- Açai powder was nutritious, energetic, with high anthocyanin content.

Açai is a nutritious and energetic food that demonstrated antioxidant activity and cardioprotective properties. However, since açai is a very perishable raw material, studies for its preservation are needed. The açai powder production is a way to obtain products with low moisture content, good stability and higher shelf life. This study aimed to investigate the feasibility of drying açai in spouted bed, evaluating the operating conditions on the yield and quality of the product. The experiments were conducted according to a central composite design. Operating variables studied were: drying air temperature, airflow rate and maltodextrin concentration. Process yield, moisture content and total anthocyanins content were analyzed as responses. The process yield was positively influenced by all the variables studied. The increase in temperature caused a significant reduction in the moisture content. Airflow rate was the variable that most influenced the degradation of anthocyanins. Applying desirability function method, an optimal drying condition was found. Such this conditions was obtained a nutritious, energetic and porous powder, with excellent flowability, low moisture and high anthocyanins content.