Impact of Wall Material Composition (Maltodextrin vs. Inulin vs. Nutriose) and Emulsion Preparation System (Nano- vs. Microemulsion) on Properties of Spray-Dried Linseed Oil.

The aim of this study was to compare the functional properties of linseed oil powders made of three types of wall material (OSA starch + maltodextrin, OSA starch + nutriose, and OSA starch + inulin) and two types of emulsion phases (micro- and nanoemulsion). For these independent variables, the properties of the prepared emulsions (flow curves and viscosity) and the resulting powders (encapsulation efficiency, particle size distribution, water activity, bulk and tapped density, Carr's index, color parameters, and thermal stability) were determined. The results showed that emulsion viscosity and most powder properties were affected by the emulsion type. All emulsions demonstrated Newtonian-like behavior, with viscosity values ranging from 29.07 to 48.26 mPa·s. The addition of nutriose induced the most significant variation in this parameter, with nanoemulsification leading to a 1.6-fold increase in viscosity compared to microemulsification. The application of nanoemulsification to prepare the emulsions prior to spray-drying resulted in powders with lower surface oil content (by 78.8-88.5%), tapped density (by 1.7-14.2%), and Carr's index (by 7.6-14.0%), as well as higher encapsulation efficiency (by 5.9-17.0%). The decreased oxidative stability (by 30.9-51.1%) of powders obtained from nanoemulsified emulsions was related to 4.7-15.9-fold lower surface oil content. Powders produced using inulin as the wall material had the smallest and most uniform particle sizes, showing minimal variation between powders derived from nano- and microemulsified emulsions.