Novel strategy for color-controllable Pickering emulsion: Location control of pigments at different phase

Abstract

To develop a novel strategy for preparing color-controllable emulsion by controlling pigments spatial location, the stable Pickering emulsion (O/W) was firstly established by using zein-chitosan nanoparticles (ZCNPs) as outer layer and medium chain triglyceride as inner phase. Three fat-soluble pigments (FSPs), curcumin, oil red and oil blue, were introduced into this emulsion system by controlling their location (in outer layer or inner phase). The physical properties, qualitative and quantitative color analysis of the emulsion were investigated by encapsulation efficiency, confocal laser scanning microscope and values of L*a*b*. The loading efficiency of ZCNPs to FSPs maintained at 87.6%–89.3%, and had 95% of oil encapsulation efficiency. Different from the blending coloring strategy, the emulsions formed in this paper showed better chroma (based on L*a*b* values) with even fewer additive pigments amount. Under the same amount of pigment, the saturation of the emulsion (FSPs in outer layer) could increase by 81.5%. This study might provide a new color control strategy for complex food systems. • The structure of Pickering emulsion was defined as outer layer or inner phase. • ZCNPs had a higher loading efficiency for the three FSPs. • Pickering emulsion stabilized by ZCNPs was stable. • Color could be adjusted by changing the location of pigments in the emulsion. • The emulsion color was more susceptible to outer layer.