Powdered oat drink production by pulse spray drying

Abstract

Oat is a well-studied food known for its nutritional properties, which provide health benefits under regular consumption. The potential of a new spray drying technology (pulse spray drying, PSD) was explored in drying oat drinks. Additionally, feed solutions were dried by traditional spray drying (SD), and the effect of maltodextrin addition was assessed. Two types of powder samples were collected: the primary powder, from the main chamber; and the overall powder, after mixing both the powder from the main chamber and the powder from the cyclone separator. Some physicochemical properties of the powders and their morphological characteristics were examined. The analyses performed did not indicate significant differences between primary and overall powders. Maltodextrin-added powders from PSD presented higher moisture, water activity (a_w), solubility, and particle size; and lower bulk and tapped densities, indicating a higher volume occupied by the particles. Color measurements (luminosity and chroma) differed between the drying treatments: a lighter coloration was observed in the SD group. Finally, images from scanning electron microscopy (SEM) revealed that the lower moisture content in the samples without maltodextrin led to a greater distribution of pores in the surface of particles. In conclusion, the data raised in this study suggest that using the PSD in combination with maltodextrin can be a good approach to dry vegetable drinks. However, other drying parameters need to be tested to improve the powder flow properties (e.g., airflow rate, atomization pressure, relative humidity, feed composition), as they are important characteristics during the processing.