Definição de condições ótimas para o processo de secagem em spray dryer da polpa de buriti (Mauritia flexuosa L.)

Abstract

Buriti (Mauritia flexuosa) is a native fruit of the Amazon, known for its functional potential, attributed to a high concentration of carotenoids. The spray drying process, in turn, can transform solution, suspensions or pastes into small droplets, which in contact with hot air produce powders with characteristics that favor the preservation of the product, in addition to facilitating storage and the transport. Thus, the objective of this work was to optimize the drying process of buriti pulp, in spray dryer, aiming to obtain a powdered product with desirable characteristics. For this, a central composite rotatable design (CCRD) was used to determine the influence of the variables: drying air temperature (130 – 190 °C), feed flow (7 – 17 mL/min) and carrier agent concentration (20 – 60%), on the product properties: moisture, water activity (aw), hygroscopicity, total carotenoid content, water solubility index (WSI) and the instrumental color parameter b* (fruit characteristic color parameter). To ensure the stability of the emulsion in the suspension, soy lecithin was added to all formulations, in the amount of 5% in relation to the dry matter of the sample. The response surface methodology (RSM) and the desirability function defined as optimal conditions for the drying process of buriti pulp: a gum arabic concentration of 60%, feed flow rate of 17 mL/min and drying air temperature of 190 °C; in the experimental domain. Under these conditions, the powder obtained had the following characteristics: 0.62 g/100 g moisture, aw of 0.16, hygroscopicity of 18.79 g/100 g, carotenoid content of 60.92 µg/g, ISA of 80.26% and a value of 31.32 for the chromaticity parameter b*.