Spray drying of high hydrophilic solids emulsions with layered interface and trehalose-maltodextrin as glass formers for carotenoids stabilization

• Single layer (SL) and layer by layer (LBL) emulsions were spray dried.
• Ability of SL and LBL powders in preventing the loss of carotenoids were determined.
• Carotenoids losses followed first order loss kinetics.
• Storage of systems above Tg delayed carotenoids losses.
• LBL system gave a better protection towards carotenoids losses.

Objectives of the present study were to spray dry high total solids content single layer (SL) and layer-by-layer (LBL) emulsions, and to compare the ability of the SL and LBL powders in preventing the loss of carotenoids upon storage in the vicinity of the glass transition temperature (Tg). Carotenoids stability in humidified spray dried (HSD), non-humidified freeze-dried (NHFD), and humidified freeze-dried (HFD) systems were determined as well. The loss of carotenoids followed first order loss kinetics. An initial rapid followed by a second slower first order loss kinetics was observed in the non-humidified spray dried (NHSD) systems. Storage of systems above the Tg delayed carotenoids losses based on the rate constants. The loss of carotenoids in LBL systems was more heat sensitive as the activation energies were generally higher. Activation energy decreased above Tg indicating that the loss of carotenoids became less temperature dependent. The application of LBL interface structure reduced the rate of carotenoids losses and can be applied to prevent loss of oil soluble bioactives in formulated materials.