Effect of guar gum on the rheological properties, microstructure and 3D printing performance of egg yolk powder-potato starch composite gel

This work explored the effects of guar gum (GG) concentration (0, 0.9, 1.8, 2.7, 3.6, 4.5 g) on the rheological properties, water distribution, microstructure and 3D printing performance of egg yolk powder-potato starch (EYP-PS) composite gels. The results showed that EYP-PS inks with GG added showed higher gel modulus, apparent viscosity, and hardness compared to the "Control". Low-field nuclear magnetic resonance (LF-NMR) results indicated that GG was able to restrict the free movement of water and promote the migration of EYP-PS to tightly bound water. The microstructure results showed that GG could induce EYP-PS to form a denser network structure, and EYP-PS inks with an appropriate amount of GG showed better springiness. Fourier transform infrared spectroscopy (FT-IR) confirmed that the addition of GG did not create new functional groups in EYP-PS, but enhanced the hydrogen bonding in the gels. Overall, GG-1.8 and GG-2.7 exhibited the best 3D printing performance and were more suitable for patients with swallowing disorders. This study contributes to the development of 3D-printed gel food containing egg yolk powder as well as exploring the effect of GG on egg yolk powder-starch composite food materials.