Modified rice protein-polysaccharide complexes as stabilizers for high internal phase emulsions in application of 3D...

This research investigated how the phosphorylation followed by polysaccharide complexation regulated the stabilization of rice protein (RP)-based high internal phase emulsion (HIPE) and improved its 3D printability. The phosphorylation modification reduced particle size of RP and increased its solubility. Xanthan gum (XG), guar gum (GG) or sodium alginate (SA) further dose-dependently (0.05-0.2%) improved the rheological and printing performance of the HIPEs, and the effects followed XG > GG > SA. There was strong electrostatic repulsion between highly electronegative XG and phosphorylated RP (PRP), resulting in the smallest particle size and the highest solubility. This promoted a higher interfacial protein adsorption (63-70%) and effectively lowered the flocculation degree, endowing the HIPE inks with superior anti-deformation ability under large amplitude oscillatory shear (LAOS) and the best thixotropic recovery (74-83%) and printing accuracy (86-99%). Additionally, XG and GG may enhance rigidity by forming weak gel networks and inter-chain entanglements separately. The PRP-SA complexes had lower interfacial activity, leading to poorer rheological properties and printability of the HIPEs. The modified ink also exhibited potential for delivering β-carotene (encapsulation efficiency >95% and bioaccessibility >56%), providing a basis for 3D printing-based precision nutrition. This study expands the application of RP in functional food ingredients.