Modulation of physicochemical properties and cooking stability in plant-based spherical egg yolk encapsulated in sodium alginate-gellan gum-chitosan composite films.

Abstract

This study developed core-shell structured spherical egg yolks with a composite shell encapsulating plant-based egg yolk liquid, using sodium alginate (SA), low-acyl gellan gum (GG), and chitosan (CS). By modulating the SA/GG ratios (2:1, 1:1, 1:2) and CS concentrations (0-0.3 %), the physicochemical properties of composite films and their effects on the morphology, texture, and cooking adaptability of plant-based spherical egg yolks were investigated. In summary, the sustained release of Ca2+ from plant-based yolk liquid induced the gelation of SA and GG, forming an entangled three-dimensional gel network that serves as the foundational structure of the interfacial film. Meanwhile, CS enhanced the interfacial film performance by forming entangled insoluble polymer complexes through electrostatic interactions with SA and GG. However, excessive CS (>0.3 %) can cause electrostatic polymer aggregation, resulting in a rough membrane surface. The mixing of SA and GG showed differentiating effects: SA-dominated systems (SA:GG = 2:1) showed enhanced water retention and cooking stability, whereas GG-rich formulations (SA:GG = 1:2) maintained better structural sphericity while improving light barrier properties. Consequently, the synergistic SA-GG-CS system effectively regulates the structure of simulated yolk membranes, enhancing the performance of plant-based spherical yolks, thereby offering a potential solution for developing spherical egg yolk products with a film-like structure.