Chewable Gelatin Emulsions for Oral Lipid Delivery: Elimination of Gastric Coalescence with κ‐Carrageenan

Abstract

AbstractGelatin‐based chewable emulsions can be a convenient vehicle for oral delivery of oils or lipid soluble bioactive components. Gelatin‐stabilized emulsions do, however, rapidly flocculate and gradually coalesce in gastric fluids. This destabilization is caused by the combined action of pepsin and mucin and is most significant at pH 3, followed by pH 2, then pH 4. Through in vitro lipolysis experiments it is shown that this destabilization leads to a decrease in emulsion lipolysis rate after incubation in simulated gastric fluids (SGFs). In this paper a potential solution to this gastric instability is suggested: inclusion of 1 wt% sodium‐κ‐carrageenan (κ‐CGN) of intermediate Mw into the gelatin emulsions. The κ‐CGN used has minimal impact on gelatin gelled emulsion properties, preserving the soft elastic gelatin texture. When these gelled emulsions disintegrate in gastric fluids, electrostatic interactions between the gelatin and κ‐CGN occur. While these interactions lead to heavy flocculation, they also protect the gelatin from pepsin action, providing full stability against emulsion coalescence during at least 2 h in SGF at pH 2–4. When the pH is neutralized upon mixing with intestinal fluids, the emulsion fully deflocculates and the rate of in vitro lipolysis is not affected by gastric residence time.Practical applications: Avoiding gastric coalescence in gelatin emulsions may lead to more reliable oral delivery of lipids or lipophilic components in gelatin‐based chewable supplements or functional foods. Keeping the emulsion droplet size stable and small until reaching the intestine may lead to more rapid and efficient intestinal lipolysis, potentially advantageous in regards to bioavailability of slowly digested oils (e.g., omega‐3 concentrate) or for people suffering from impaired lipid digestion. These findings may also be applicable to emulsion systems stabilized by other proteins.