Abstract: This research aimed to develop novel complexes between walnut proteins and pectin to be used as a delivery system for curcumin. Curcumin was successfully encapsulated in pectin-walnut proteins stabilized emulsions. After 14 days of storage, the particle size (D4,3) of the curcumin-encapsulating emulsions increased slightly, and no phase separation occurred. Under ambient pressure, the pectin-walnut albumin stabilized emulsion encapsulating curcumin showed good stability against salt (up to 300 mmol/L) and heat (up to 90 ℃). The pectin-walnut globulin stabilized and pectin-walnut glutelin stabilized emulsions encapsulating curcumin showed instability against salt (100 mmol/L). During in vitro digestion, the pectin-walnut albumin stabilized emulsion could quickly release the encapsulated bioactive substances. The pectin-walnut globulin stabilized emulsion was a suitable encapsulating material, which could maintain the stability of the encapsulated curcumin in acid medium, and delay its release during in vitro digestion, improving its bioaccessibility and making it easier to be absorbed by the small intestine. However, the pectin-walnut glutelin stabilized emulsion could delay the release of the encapsulated curcumin during in vitro digestion, resulting in low bioaccessibility. The current work indicated that the pectin-walnut proteins stabilized emulsions could be applied as an effective delivery system for bioactive compounds in a wide range of functional foods.

Key words: curcumin; pectin-walnut proteins stabilized emulsion; stability; in vitro digestion