Effect of carrageenan on stability and 3D printing performance of high internal phase pickering emulsion stabilized by soy protein isolate aggregates under neutral condition.

High internal phase Pickering emulsion (HIPPE) stabilized by heat induced soy protein isolate aggregates (HSPI) alone had limited stability and poor 3D printing performance. While there is few research about HIPPE stabilized by HSPI and polysaccrides at neutral pH condition, where HSPI and ĸ-carrageenan (CG) were combined to fabricate HIPPE in this research. It was found that the incorporation of CG significantly decreased the droplet size and improved the storage stability of the resulting HIPPE. Moreover, the presence of CG improved the freeze-thaw stability of HIPPE after one freeze-thaw cycle. In addition, the addition of CG significantly improved the structural integrity of the 3D printed HIPPE and enhanced the printing precision. This was because the presence of CG decreased the interfacial tension, increased the zeta potential and viscosity of HSPI-CG, thus promoting the adsorption of particles to the oil-water interface more effectively. Moreover, the presence of CG significantly enhanced the viscoelasticity of the resulting HIPPE. These results can be further attributed to the strong hydrogen bonding and hydrophobic interaction between HSPI and CG at neutral pH condition, which can be confirmed from results of Fourier-transform infrared spectroscopy and Isothermal titration calorimeter. So the incorporation of CG endowed HIPPE with more excellent properties at a lower solid particle concentration.