Transglutaminase crosslinked fish gelatin emulsion gels: Structure, rheology behaviors, and delivery functionality

Gelatin-based emulsion gels with transglutaminase (TG) crosslinking exhibit significant potential for delivering fat-soluble bioactive compounds in functional foods. However, the effects of TG-induced structural modifications on the release behavior and stability of encapsulated compounds during storage and digestion have rarely been investigated. In this study, beta-carotene was encapsulated into emulsion-filled gelatin gels to investigate the influence of TG crosslinking time on their structural, mechanical, and functional properties. The result showed that at 4 degrees C, physically crosslinked FG emulsion gels were thermally reversible, exhibiting higher Young's modulus and storage modulus covalently crosslinked TG gels. Large amplitude oscillatory shear analysis revealed that gels formed by gelatin self-assembly were more fragile, more susceptible to nonlinear behavior, and transitioned more quickly to Newtonian fluid dissipation. Increasing the TG crosslinking duration enhanced gel rigidity, particularly at room (25 degrees C) and physiological (37 degrees C) temperatures, by forming a more compact network. However, excessive crosslinking reduced the flexibility and energy dissipation capacity of the gels. Importantly, TG crosslinking significantly improved the storage stability of beta-carotene, enhanced its bioaccessibility, and increased its stability during simulated gastric digestion. The findings of this study offer a promising strategy for structuring gelatin-based emulsion gels with enhanced stability, controlled release, and improved bioactive delivery performance.