Design of multiple emulsion structures and potential food applications

Possible application of double emulsions in the healthy food production include reducing fat content, improving fat acid profile, encapsulation of functional components, and reducing sugar / salt content of foods by increasing perception of taste intensity. In this study, three different emulsion systems for enhancing the saltiness, sweetness perception and encapsulating the iron component were designed and characterized. In the study, briefly the stability of the single emulsions, which will form the multiple emulsions, was studied. The primary emulsions to be prepared to increase sweetness and salinity perception was examined in terms of phase separation and the primary emulsion to be prepared for iron encapsulation was also examined for oxidative stability. The effect of lipophilic emulsifier (PGPR) concentration, water phase composition and oil: water phase ratio on stability was investigated in the emulsions prepared to increase the taste perception; PGPR in a concentration of 4% by weight, water phase ratio of 60:40 oil: water phase ratio and magnesium chloride content in internal aqueous phase was found effective in the preparation stabile primary emulsion. For the primary emulsion prepared for iron encapsulation, it was also found that addition of whey protein isolate to emulsions was significantly increased the oxidation stability (p <0.05). In the study, the multiple emulsions were prepared with three different external water phases: single emulsion ratio and the emulsions were evaluated in terms of droplet size, microstructure, rheology, in vitro lipid digestibility, iron bioavailability. It was determined that the ratio of external aqueous phase: single emulsion has effect on the droplet size and viscosity of all emulsions obtained (p <0.05). The emulsion with a 60:40 ratio had the highest viscosity value and the lowest droplet size. It was determined that the ratio of external water phase to single emulsion had no effect on lipid hydrolysis of double emulsions prepared to increase taste perception. Iron bioavailability decreased with increasing external water phase ratio while encapsulation efficiency increased. The multiple emulsions prepared to increase the saltiness and sweetness preception were found different from the primary emulsions containing the same salt and sugar amount at the level of p <0,001. Sixty-eight percent and 75 % of the participants found the multiple emulsions more salty and sweety compared to the single emulsions, respectively. The information obtained from this study is important in that it allows for the design of multiple emulsion systems that enhance the tase of foods to reduce salt and sugar content and encapsulate iron with high encapsulation efficiency and bioaccessibility.