Emulsification and gelation as a tool for iron encapsulation in food-grade systems

In this study, food-grade microencapsulation systems - double emulsions and water-in-oleogel dispersions were developed as carriers for iron. Double emulsions with iron located in different water phases were produced and characterized by stability, droplet size, rheology, and iron entrapment efficiency. The effect of carnauba wax and beeswax concentration (30, 50, 100, 150 g/kg) on the physical and chemical stability of water-in-oleogel dispersions as well as the ability to encapsulate iron were examined. It was determined that the location had a great impact on the droplet size, viscosity, stability and encapsulation efficiency of iron. Double emulsion with iron located in the inner water phase showed encapsulation efficiency higher than 95%. Water-in-oleogel dispersions, solidified with beeswax exhibited higher firmness (0.6-29.6 N) and encapsulation efficiency (19-100%) values, in comparison with systems structured with carnauba wax. These systems were also characterised as more stable under dynamic conditions The microstructure of water-in-oleogels dispersions also caused a delay of lipid oxidation during the whole period of storage as after 60 days of storage peroxide value was 20-30 meq/kg. Meanwhile, iron location affected oxidation rate in double emulsion samples whereas iron in the outer phase caused the highest peroxide value (similar to 50 meq/kg).

Automated summary

Food-grade microencapsulation systems including double emulsions and water-in-oleogel dispersions were developed as carriers for iron. The position of iron in these systems significantly affected their properties such as stability, viscosity, and encapsulation efficiency. Iron located in the inner water phase showed higher encapsulation efficiency, while water-in-oleogel dispersions solidified with beeswax exhibited higher firmness and encapsulation efficiency compared to those structured with carnauba wax. These systems also demonstrated improved stability under dynamic conditions. The microstructure of water-in-oleogel dispersions also delayed lipid oxidation during storage. Meanwhile, iron location affected the oxidation rate, with iron in the outer phase causing the highest peroxide value.