Dispersibility and morphology of spray-dried soy powders depending on the spraying system

Abstract

The aim of this study was to elucidate the factors affecting the dispersibility and morphology of soy powders. The influences of the configuration of a spraying system (CSS) on particle size and dispersibility of soy powders were investigated. The dispersibility, morphology, and particle sizes of powders produced using a wheel and those obtained using a nozzle differed. A moderate increase in particle size (from 15 to 24 μm) improved powder dispersibility in most cases. At a total protein content in the powder (w/w%)/total solids in the concentrate (w/w%) ratio of between 30/20 and 35/20, using the wheel significantly increased particle size (from 23 to 40 μm) in comparison to nozzle (from 14 to 20 μm); moreover, this increase in particle size was correlated to increase in dispersibility (r 2 = 0.90). These results are in agreement with published findings showing that a surface area that is too large (small particles) can lead to poor dispersibility of a powder in the case of both whey protein and micellar casein. In addition, the wheel provided a smaller span of particle sizes than the nozzle. The powders obtained with the wheel were therefore more homogeneous than those produced with the nozzle, making them easier to characterize in terms of functional properties. In summary, the dispersibility of soy powders depends on CSS with the wheel providing the most dispersible particles.