Abstract: The effects of different edible oils, proteins and maltodextrins with different dextrose equivalents (DE) on the appearance and stability of an emulsion which can be used in foods for special medical purposes were investigated by measuring the color, turbidity, rheological properties and centrifugal sedimentation rate of the emulsion. The effect of pH on the properties of the emulsion with optimized levels of three macronutrients was further explored. The results showed that all five oils had little effect on the chromaticity of emulsions. The turbidity and solar reflectance index (SRI) (A800 nm/A400 nm) of soybean oil emulsion were higher than those of the other oil emulsions, but soybean oil emulsion showed lower centrifugal precipitation rate and higher viscosity value, indicating that it was the best choice for the preparation of an emulsion. Whey protein-stabilized emulsion had better color but significantly poorer turbidity, viscosity and centrifugal precipitation rate than sodium caseinate-stabilized emulsion. Among the sodium caseinates tested, CN-EM7-stabilized emulsion showed minimum turbidity and centrifugal sedimentation rate and maximum emulsion viscosity. Additionally, maltodextrins with different DE values exhibited different effects on the quality of emulsions, and maltodextrin DE15-containing emulsion displayed the best appearance acceptance and stability. Furthermore, pH showed a significant effect on the quality of the emulsion. pH in the range of 6.50–7.00 was suitable for the preparation of the emulsion in the present research. The emulsion prepared at pH 7.00 had the highest viscosity and the minimum centrifugal precipitation rate. The most suitable types of three macronutrients and the optimum processing pH were obtained for emulsion preparation, which will provide a theoretical guidance for the industrial development of emulsion-type foods for special medical purposes (FSMP).

Key words: macronutrient, pH, emulsion, foods for special medical purposes, stability