Preparation and characterization of double emulsions for saltiness enhancement by inhomogeneous spatial distribution of sodium chloride

In this study, it was aimed to formulate primary (W-1/O) and double (W-1/O/W-2) emulsions in order to increase the perception salt placed in the external aqueous phase of the double emulsion when the amount of salt is the same in double emulsion and the control (oil-in-water emulsion). Emulsifier concentration, aqueous phase composition and water: oil ratios were investigated to obtain a stable primary emulsion. Then, with these results, double emulsions were designed at external water phase ratios (W-1/O: W-2), 40:60, 35:65 and 30:70 by weight. Characterization of double emulsions was evaluated by particle size; rheology and optical microscopy were analyzed. The digestion behaviors of compositions (oil and protein) of emulsions were studied by in vitro lipid and protein hydrolyzes to discuss in relation the compositional effects of emulsions on the kinetics and degrees of hydrolysis. Results showed that W-1/O: W-2 ratio affected the droplet size, viscosity of emulsions but no effect was determined on lipid hydrolysis. At a ratio of 40:60, viscosity was found highest, whereas droplet size was lowest. Saltiness perception of double emulsion was evaluated using directional triangle test and the double emulsion containing the same salt amount with the control (oil-in-water as control) was found significantly different (p < 0.001). The 68.18 percent of panellists was found the double emulsion saltier. The results of this study may be useful for development of emulsion-based foods, such as salad dressing, that have both reduced salt and fat content.