No abstract

Refractance window (RW) drying is considered an emerging technique in the food field due to its scalability, energy efficiency, cost and end-product quality. It can be used for obtaining flakes from high-oleic palm oil (HOPO) nanoemulsions containing a high concentration of temperature-sensitive active compounds. This work was thus aimed at studying the effect of temperature, thickness of the film drying, nanoemulsion process conditions, and emulsion formulation on the flakes’ physical properties and microstructure. The results showed that HOPO flakes had good physical characteristics: 1.4% to 5.6% moisture content and 0.26 to 0.58 aw. Regarding microstructure, lower fractal dimension (FDt) was obtained when RW drying temperature increased, which is related to more regular surfaces. The results indicated that flakes with optimal physical properties can be obtained by RW drying of HOPO nanoemulsions.

Nanoencapsulation is an efficient process to incorporate high nutritional oils, such as high oleic palm oil (HOPO). Several drying technologies can be applied for obtaining HOPO powders. The aim of this work was to study the effect of two different drying methods (spray-drying, SP and freeze-drying, FD) on some physical properties and microstructure of powders obtained from HOPO nanoemulsions. Results showed that FD powders presented lower aw and bulk density, and higher dissolution rate than SD powders. Results suggest that SD could be a more economical alternative to FD in order to obtain HOPO powders with low moisture and aw.