Development, characterization and underling mechanism of 3D printable quinoa protein emulsion gels by incorporating of different polysaccharides for curcumin delivery

Emulsion gels stabilized by food-grade polymers such as proteins and polysaccharides are edible 3D food printing inks with various applications in food industry. In this study, 3D printable quinoa protein emulsion gels with four polysaccharides incorporated were fabricated to delivery curcumin. The effect of inulin (INU), fucoidan (FU), dextran sulfate (DS), and sodium alginate (SA) on the microstructure, rheological properties, and 3D printing performance of quinoa protein emulsion gels were all investigated. The results showed that the incorporation of four polysaccharides promoted formation of tightly packed oil droplets within gel networks, along with enhancing hardness, water holding capacity, freeze-thaw stability and decreased swelling ratio of the QP emulsion gel. All samples exhibited shear thinning behavior and polysaccharides increased viscoelasticity of QP emulsion gel. The hydrophobic interactions and disulfide bond are the main chemical molecular force of emulsion gels, INU significantly increased the hydrogen bonds interactions, and anionic polysaccharide (FU, DS, and SA) significantly increased the electrostatic interactions. QP-INU exerted best printing performance as identified by preferable self-supporting capability and high line printing accuracy. The addition of polysaccharides improved the encapsulation efficiency of Curcumin in QP emulsion gel. In vitro release property showed that FU increased the bioavailability of curcumin, DS and SA decreased bioavailability of curcumin with delayed digestion rate. This study demonstrated the potential of utilizing polysaccharides to improve the flexibility of QP emulsion gel for 3D printing functional food.