In this study, a novel approach to prepare spray-dried encapsulated curcumin powder was investigated. The effects of surfactants viz. Tween 80 (at 0.25 to 0.75% wt) and lecithin (at 1% wt) and of a stabilizer viz. chitosan (at 0 to 0.375% wt) on the characteristics of curcumin-based emulsions as well as on physicochemical properties of the resulting spray-dried encapsulated powder were determined. The optimal emulsion was noted to be the one formulated with 0.50 and 0.25% wt, respectively, of Tween 80 and chitosan (T0.50/C0.25). Spray-dried powder prepared from the optimal emulsion was compared to that prepared from an emulsion with 0.5% Tween 80 and 0% chitosan (T0.50/C0.00), as well as that from an emulsion with 0.25% Tween 80 and 0.25% chitosan (T0.25/C0.25). Physical properties of all powders were not significantly different. However, the encapsulation efficiency of T0.50/C0.25 powder (72.28%) was significantly higher than those of T0.50/C0.00 (47.19%) and T0.25/C0.25 powder (51.61%). Ferric reducing antioxidant powers of T0.50/C0.25 and T0.25/C0.25 powders were comparable but significantly higher than that of T0.50/C0.00 powder. After reconstitution, the mean particle sizes of T0.50/C0.25 and T0.25/C0.25 remained unchanged due to the protection by chitosan. T0.50/C0.00 powder was noted to exhibit the highest bioaccessibility (89.32%) in the simulated gastrointestinal tract. PRACTICAL APPLICATION: The results of this study can be used as a guideline to develop a stable formulation of curcumin feed emulsion that can later be transformed into an encapsulated powdery form via spray drying. Such a guideline should prove useful for a company looking for a way to produce high-quality functional ingredients and/or products from curcumin.
Keywords: antioxidant activity; bioaccessibility; emulsion stability; encapsulation efficiency; simulated digestion; spray drying.
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