Curcumin and catechin co-loaded water-in-oil-in-water emulsion and its beverage application

• Curcumin and catechin co-loaded double emulsion was fabricated.
• Preformulation studies were conducted to evaluate the suitability of co-excipients.
• Catechin was encapsulated within the inner aqueous phase of double emulsion.
• Curcumin was encapsulated in the oil phase of double emulsion.
• WOW emulsion increased the stability of curcumin and catechin in beverage system.

Curcumin and catechin are nutraceuticals and natural health products that have shown several health benefits. However, due to their unstable nature, these compounds cannot be included in food products as such. The prime objective of the current study was to examine the formulation factors that determine the stability of these nutraceuticals and their carrier systems as well as to fabricate water-in-oil-in-water emulsions (W/O/W) to prevent the degradation of both curcumin and catechin in beverage systems. The fabricated emulsion had a volume-weighted mean diameter (d43) of ~4 µm, with an encapsulation efficiency of >90%. Encapsulating the catechin within the inner aqueous phase of the double emulsion increased the stability of catechin by >20% at 23 ± 2 °C and by >40% at 4 °C after 15 days of incubation, as compared to free catechin. In the case of curcumin, >80% was detected after incubation in the beverage system in the form of emulsions, whereas it was reduced to ~40% in the case of free curcumin.