Encapsulation of oil in powder using spray drying and fluidised bed agglomeration

摘要

Many food active molecules such as antioxidants and aromas, exist in an oil form which may be easily oxidised. They are often prepared as a dosed, free-flowing powder, for storage protection and controlled release purposes. Oil encapsulation in powder was tested using a vegetable oil (VO) chosen as a model (5% w of dry matter) with a support of maltodextrin (MD) and acacia gum (AG) (ratio 3/2 w/w). Spray drying of a formulated aqueous emulsion (VO/MD/AG) led to small particles (< 50 μm ). Further, their size was increased (150 μm) by agglomeration in an air fluidised bed with spraying of water. Direct agglomeration of maltodextrin with an aqueous emulsion (VO/AG) represents a good process alternative, leading to particles of 200 μm. The two agglomerated powders consist of 5% of oil well dispersed in the support (MD/AG), with less than 0.5% on the particles surface. The protection against oil oxidation is good in comparison with unencapsulated oil. Also the agglomerated powders have suitable properties of flowability and wettability.